Talk:Skull Cavern

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Shaft Chance

Is it safe to assume that shafts chance to appear is the same as stair chance. where stairs can appear exposed or under rocks just as much as shafts do? NotJoshuaNotJoshua (talk) 10:11, 24 April 2021 (UTC)

20% chance that a ladder will become a shaft/chute/hole, so 1 in 5. Not in infested floors. Dubesor (talk) 15:29, 24 April 2021 (UTC)

Prehistoric Levels

Are Prehistoric Levels more common in 1.5? The Wiki says the odds are 2.2%. Before the wiki was updated about a month ago, it said nothing about odds. I seem to remember seeing 1% somewhere, which is consistent with my experience with 1.4. I just got three prehistoric levels in a trip to Level 100 with staircases, so I was wondering if I got lucky or if the odds went up. Now I'm wondering, did the odds go up, or was I just unlucky before? There's nothing about it in the Version History. If it did change, it might be worth noting in the History section, but is there any evidence of it? Zendowolf (talk) 07:14, 5 June 2021 (UTC)

The code from 1.4 and 1.5 is the same, so I think you're a victim of RNG. margotbean (talk) 17:42, 5 June 2021 (UTC)

Dark Cowboy Hat

It looks as the Dark Cowboy hat is missing in the treasure room list, so the chance finding the other 1/25 things schould be 1/26 but I'm not sure what with the more rare items or the seeds happens... Botautal (talk) 10:32, 1 August 2021 (UTC)

I'll fix that asap. It will be a nice break from adding movies & concessions tastes to all 34 villagers in all 12 languages. 😁 Thanks for pointing that out; I actually found one of those in my current playthrough and completely forgot to make a note of it for the wiki! margotbean (talk) 17:33, 1 August 2021 (UTC)

The Dark Cowboy Hat and the Auto-Petter were the only items added with v1.5. I believe I've adjusted the chances to find them correctly. Thanks again, margotbean (talk) 19:34, 1 August 2021 (UTC)

Rhubarb Pie

A monster just dropped a Rhubarb Pie when I killed it in the dangerous Skull Cavern (Skull Cavern Invasion quest active). It was either a Royal Serpent or a Giant Purple Slime (most likely a slime). This is not covered by the special items in The Mines#Special Items, including the "random item from a treasure room". I've checked MineShaft::getTreasureRoomItem, and the possible cooked dishes have not changed.

I've received a lot of other seemingly strange drops, but they've all been explained by either Special Items or the Pink Cake inside the Giant Slime... this one I can't explain.

Clearly there's more code-diving to be done on dangerous monster or dangerous Skull Cavern drops. margotbean (talk) 01:00, 28 November 2021 (UTC)

Could you have destroyed a crate/barrel at the same time? Rhubarb pies can drop from those if in dangerous mines/skull caverns. BlaDe (talk) 07:33, 1 December 2021 (UTC)

At the time I did not think so, since this is a recurring theme with me... I had cheats on so I was invincible, so I could concentrate on what was dropping what. Still, it doesn't make sense otherwise, so I have to conclude it was a crate or barrel. Assuming I can get the decompiled v1.5.5 code to run, I should be able to investigate these kinds of oddities better myself. 🤞 ;) Thanks, BlaDe! margotbean (talk) 19:21, 1 December 2021 (UTC)

Floor layouts and themes

Since The Mines page says the layouts and themes for floors, would it make sense if the Skull Cavern page did also? because I feel a bit empty about it, for example, floors 33, 73, and 113 being a star shape. 9000 (talk) 8:47, 25 July 2022 (UTC)

If you can find a code reference that shows the layouts aren't completely random, then we can add it to the page. margotbean (talk) 15:11, 25 July 2022 (UTC)

The code would say otherwise. The only Skull Cavern level with a fixed layout is 100 (coded as 220), using the same layout as level 10 of the Mines. - IBugOne (talk) 18:49, 25 July 2022 (UTC)

There's a block in MineShaft.loadLevel (starts with if this.getMineArea(level) == 121, which corresponds to the skull cavern) that randomizes the floor layout choice for the skull cavern. --Atravita (talk) 20:57, 25 July 2022 (UTC)

Since of the floor layouts being randomized every time The Player visits them is not correct per se. It is because the only floors that have matching layouts is floor 100 and treasure rooms, which uses floors 10, 30, 40, 50, 70, 80, 90, 110, and 120 from The Mines. So IBugOne is correct about this research. Here are the floor themes: The floor layouts for floors 1-29 of The Mines has a desert theme, and the last 10 levels theme has an Egyptian tomb theme. 9000 (talk) 9:56, 27 September 2022 (UTC)

Integer Limit being 120 less

Since of the bug where placing a fence on floor 120 and blowing it up by a bomb created a ladder going to floor 1 of the Skull Caverns, so that means floor 1 of the Skull Caverns is floor 121 of The Mines, while the wiki page says 2147483647 instead of 2147483527, feel free to check the game code for correction. If it is 120 less, feel free to change the text. 9000 (talk) 9:00, 30 August 2022 (UTC)

You're right about this. The game code recognizes Skull Cavern floor N as Mines floor N+120, so I wouldn't be surprised to see the SC limit being 120 less than the integer limit. However, the page text says 2147483647 is the integer limit, which is correct per se. Also since this is only a "gotcha"-type of trivia, I'm not sure changing that reflects anything meaningful. - IBugOne (talk) 15:15, 30 August 2022 (UTC)

Lava Bat floors

Since of our wiki says that the Lava Bats spawn on the first 50 floors, which is not correct. Each time we play, the only floors we see them on are floors 20 and 40 on non-Mummy levels. 9000 (talk) 8:27, 11 September 2022 (UTC)

If you can find proof that it's not random in the game code, then we can change the wiki. margotbean (talk) 18:29, 11 September 2022 (UTC)

In the function to populate the levels (StardewValley.Locations.MineShaft.getMonsterForThisLevel, which in turn is called from StardewValley.Locations.MineShaft.populateLevel), has a few sections to generate a bat.

The first is for Dino floors, which result in an iridium bat, then there are the options for the mines, then for Skull Cavern, there are 2 options to generate a bat, with the conditions:

(this.mineLevel % 20 == 0 && distanceFromLadder > 10f) or (this.mineRandom.NextDouble() < 0.33 && distanceFromLadder > 10f && this.mineLevel >= 171)

The first case matches the claimed behaviour of only seeing them on floors 20 and 40; and the latter case will produce an iridium bat.

Additionally, before either of these checks, it checks if it is loaded a DarkArea, in which case it will only spawn a ghost or a mummy.

However, further down in the populateLevel function, it also checks (this.mustKillAllMonstersToAdvance() && this.EnemyCount <= 1), and adds a bat if true. But this doesn't specify the level so it should be a normal bat, not a lava bat.

The only other location I can find it spawning a bat is in StardewValley.Locations.MineShaft.spawnFlyingMonsterOffScreen

In this case, for the Skull Cavern, it first checks (this.mineLevel < 171 || Game1.random.NextDouble() < 0.5) and if that is true it will spawn a serpent, if it is false it will spawn a bat.

So unless I am missing something, the only options for bat spawns are:

• Normal bat spawning if you need to kill all the monsters to advance and no monster spawned.
• Lava bat spawning on level 20 and 40 (given it is not a dark area).
• Iridium bat spawning on level 51 and above, either on screen during the normal population event, or offscreen while still on the floor.

So Lava bats should only spawn on level 20 and 40. I'll update the main page to say that.JackBlack69 (talk) 07:54, 3 January 2023 (UTC)

Thank you very much for that thorough analysis!! margotbean (talk) 18:45, 3 January 2023 (UTC)

Ore distribution bug?

While looking at the code for ore distribution, I found the ore distribution for iron and copper to be quite strange. The chance for iron is calculated as:

chanceForIron = Math.Min(0.5, 0.1 + (double)(this.mineLevel - Math.Min(200, skullCavernMineLevel)) * 0.005)

But as mineLevel is always 120 more than skullCavernMineLevel, this can be rewritten as:

chanceForIron = Math.Min(0.5, 0.7 + (double)(skullCavernMineLevel - Math.Min(200, skullCavernMineLevel)) * 0.005)

And as the minimum of skullcavernMineLevel and 200 cannot be larger than skullCavernMineLevel, this latter term will always be greater than 0, so this simplifies to:

chanceForIron = 0.5

Practically this means iron and copper are equally rare. (And the check only occurs after passing an ore check and failing an iridium check and a gold check). But if this was intended, it makes much more sense to just use 0.5. This makes me think it is likely a bug, and that both were meant to use mineLevel (or both were meant to use skullCavernMineLevel) JackBlack69 (talk) 11:35, 18 April 2023 (UTC)

This would be a good candidate to be reported as a bug on the official forums (link in left sidebar); there is a thread specifically for reporting bugs. CA likes to keep the game balanced, so he'd probably like to know if there's a mistake. margotbean (talk) 18:23, 18 April 2023 (UTC)

Chance for a Prismatic Shard from a Treasure Chest

Since finding Prismatic Shards is rare enough, it is estimated that Prismatic Shards have a 1/26 chance of spawning inside a Treasure Chest in the Skull Caverns, this is not actually true, it should be a 4% chance of spawning. Refer to the game code for details. 9000 (talk) 9:21, 29 June 2023 (UTC)

MineShaft::getTreasureRoomItem specifies 26 items that can be obtained; some items contain a range of values (like cooked dishes), so the 1/26 chance has to be multiplied by the number of items. Otherwise, like for the Prismatic Shard, the chance is 1/26. margotbean (talk) 18:43, 29 June 2023 (UTC)

Teasure rooms table broken

Hi sorry I didn't know how to report this, but the table under the "Treasure Rooms" section that should display all possible treasures that can be randomly found inside Treasure Chests in the Skull Cavern, is not displaying. Not sure how to fix it. Thanks! Ebi (talk) 05:38, 25 August 2023 (UTC)

Looks fine to me, you have to hit the link to make it expand though. Atravita (talk) 13:35, 25 August 2023 (UTC)

Pre historic levels

According to stardewvalley predictor the prehistoric levels have choosen persistent floors each days and can be re visited again however floor maps that are choosen randomly each time the player uses stairs or shafts to go next next floor can be eligible or not,changing the predictions to find them on those floors Void farmer (talk) 20:17, 9 October 2023 (UTC)

So basically they may or may not be persistent, from the player's point of view. I'll remove the statement, and please keep in mind that v1.6 is going to change a lot if things that are predictably random to be not predictable. MouseyPounds is not upddating the stardew predictor, so it may become obsolete. margotbean (talk) 20:21, 9 October 2023 (UTC)

While I do agree that it remains to be seen if they will be fixed per day in 1.6, my understanding was that the main elements targeted were things like clay farming. After the update I will have a look at the code and see what it is like. If it does change in 1.6, it may be good to just have it as a note that prior to 1.6 each day only selected floors could be prehistoric floors. JackBlack69 (talk)

That's what the "Version History" section is for! margotbean (talk) 00:00, 11 October 2023 (UTC)

It'll still be predictable just with less of a pattern. Still a seeded random. Atravita (talk) 10:00, 11 October 2023 (UTC)

Realised I never got back to this. This, like the other similar predictable things can now either use the legacy random option, or the new still deterministic hash based random. Both of these are still deterministic. The distinction is that the legacy option just used simple addition while the new one uses a hash algorithm. This means you don't get the same patterns in predicted values. e.g. for clay farming you could till a square, then move a particular set of values to till the next, but can't with the hash based algorithm. Getting clay is still entirely deterministic, and can be predicted with tools, just not easily without an program calculating it like you could before. The prehistoric floors remain predictable in the sense that a program can predict what it will be, and only a permitted set will be on a given day (and seed). So for a casual player, the behaviour is the same, if they go through skull cavern multiple times in a day, then on each trip down some floors will be either mummy (or a particular set) floors or normal floors; while others will be mummy (or a particular set) floors or prehistoric floors. JackBlack69 (talk) 10:38, 10 July 2025 (UTC)

Trinkets in treasure rooms

New contributor so I don't know whether y'all happen to know this already, but at least fairy box (perhaps all trinkets) can be found from Treasure Rooms in Skull Cavern. Found one in a (non-dangerous) Skull Cavern run, so I just thought i'd mention since i didn't see it listed on this page or the pages for trinkets generally. BeanieQueenE (talk) 04:04, 25 March 2024 (UTC)

Hey, new contributor here too. I also saw that trinkets were dropping from the treasure room chests an didn't see it on the wiki so took it upon myself to take a look. In the decompiled code you can see that all of the trinkets are able to drop IFF the player has the combat mastery unlocked (4.5% chance). Additionally, Golden Animal Cracker's can drop if the player has the farming mastery unlocked. I updated the page earlier today. Gruyere (talk) 19:22, 29 March 2024 (UTC)

Trinket drop rate location/level/monster dependent?

I have noticed that i get a LOT of golden spur from mummy level (i think from ghosts), and sometimes my dive will give me duplicates of one or two trinkets. wonder if there's anything to do with the monster slain, lvl i'm on, or just a random daily seed. Jjiang31 (talk) 04:20, 25 March 2024 (UTC)

Shrine of Challenge

Is it worth adding some text explaining how the Skull Cavern version of the Shrine of Challenge works? I had some questions about it and had to dig around reddit to find an explanation. Maybe it should be here. E.g., Do both shrines impact both the skull cavers and the mines? Does it take effect immediately? What are the effects of it in the skull caverns? Etc.. All the topics that are included in the wiki for the Mines version of the shrine should probably be covered here too. Or is there some reason for omitting it? Rossc719 (talk) 21:27, 28 September 2024 (UTC)

Yes, I think it would be worth explaining the specifics in as few words as possible, similar to the Mines page. margotbean (talk) 17:50, 29 September 2024 (UTC)

Iridium Snake Milk

On floor 100 of the Skull Cavern, after reading the Secret Note #10, the player meets Mr. Qi and can drink the Iridium Snake Milk if desired. It is not required, but if they do, they will permanently increase the player's max health by 25 points, AND drain 2 energy temporarily. This should be added to the wiki. Players should have food with them to fix it, but this info is nowhere in the wiki. It should be added. Great Game 222 (talk) 8:28, 12 February 2025 (EST)

Apparently someone tried to add this already but an admin locked the page as a result and reverted the edit. SomeoneIGuess (talk) 04:43, 13 February 2025 (UTC)

I believe that stating that Iridium Snake Milk drains 5 energy is relevant. It can cause people to exhaust, and if they had known this information they could have eaten before entering 100. It has also been relevant to two no energy challenge runs I have seen. What are the arguments that it is not? BlaDe (talk) 22:03, 13 July 2025 (UTC)

Nice to see you on the wiki, BlaDe! I suppose the main argument against adding it is that it's already on the page... margotbean (talk) 03:08, 14 July 2025 (UTC)

Huh, suppose I should have looked at the current version. My bad! BlaDe (talk) 03:12, 14 July 2025 (UTC)

Mummy floors

Hello! This page has sections for specific floor like the Prehistoric floor, however there isn't a section for the Mummy Floors. I think it would be very important since The Mines page, for example, has sections for every floor type with very distinct characteristics.

The Mummy page says that it spawns on the Skull Cavern, which is not precise. Later, it describes the appearance of a mummy floor "Mummies spawn in rooms resembling an Egyptian tomb, which appear randomly throughout the caverns. There is also a need for it on the Carbon Ghost page: "They only appear on Mummy levels" Adding a section for it would greatly help, Can I? Klytos (talk) 19:44, 26 January 2026 (UTC)

Shrine of Challenge Continued

I'm not sure if this is what you were getting at, but I think there should be a discussion of difficulty levels. The page for The Mines has a section for that, explaining how the mines become double-difficult if the quest is active while you've also activated the shrine. From experience, the Skull Caverns definitely seem to have a similar dynamic. (E.g. Squid Kids take me two hits to kill with the shrine on without the quest active, but three hits to kill with the shrine on and quest active together.) Strangely, I can't find anything at all online referencing the double-difficult state for Skull Caverns - only for the regular mines. ChloeCat (talk) 01:01, 4 March 2026 (UTC)

It would be great if someone would look at the game code and elucidate the details of difficulty for the skull cavern! Pending that, in-game observation only gives us the fact that they are "more difficult"...

The dangerous monsters' details are already on their respective pages, so there's that. margotbean (talk) 02:08, 4 March 2026 (UTC)

Agreed! Maybe I can do some digging in the code. It doesn't look like the dangerous monster pages acknowledge differences in double-difficult state. I also just noticed that Squid Kids aren't mentioned as a monster on the Skull Caverns page at all. The Squid Kid (dangerous) page does mention that they appear in Skull Cavern when the quest is active, but that also doesn't acknowledge that they appear there when the shrine is active (even when the quest is not). It seems like some things just haven't been updated to reflect the fact that the difficulty of Skull Caverns can be toggled outside of the quest now (since it used to just be the quest that determined difficulty, with no shrine). ChloeCat (talk) 02:48, 4 March 2026 (UTC)

Okay, haven't dug too deeply yet (hadn't ever looked at Stardew Valley's code specifically before), but I believe the quest and the shrine both trigger SkullCavesDifficulty++, through a process similar to the regular mines and with similar effects. ChloeCat (talk) 03:26, 4 March 2026 (UTC)

I think the Difficulty Levels section of the The Mines page could essentially be copy-pasted here, except of course changing "Mines" to "Skull Caverns", "Shrine of Challenge" to whatever it's called in the Skull Caverns if it technically has a different name, the name of the quest, and removing the reference to spiders. If needed, I can cite specific references in the code, although I'm guessing that's unnecessary since there don't seem to be references in that section on the The Mines page. Of course, if anyone else has looked in the code in more detail and noticed that I'm off about something, I'd love to hear about it! But this is how it seems to me from what I've dug into there with the SkullCavesDifficulty. (Sorry for making several comments - not sure if that's discouraged. Just wanted to update with the information I've learned through my read of the code.) ChloeCat (talk) 04:36, 4 March 2026 (UTC)

Ha ha, yes, I was thinking the Mines section could use a code reference...

If you would like to update the Skull Cavern page, that would be fantastic! I do think a code reference would be a very good thing to add to it, though. If you would. Thank you so much for your comments and your research! margotbean (talk) 18:02, 4 March 2026 (UTC)

Sounds good! I will probably look into it a little more later and make those edits. Do you know if there is a copy online of the decompiled game code for 1.6.15? Most recent I can find on GitHub is 1.6, and while I don't see anything in changelogs suggesting these sections of the code would be different between those versions, I'd still like to verify before citing the code. On my phone right now so not easy to just decompile myself. If there isn't a copy online, I can do it on my computer later. ChloeCat (talk) 18:45, 4 March 2026 (UTC)

Can confirm. In Game1._newDayAfterFade, if the shrine is toggled on, this increments the difficulty; and when the special order is activated in SpecialOrders.SpecialOrder.AddSpecialRule, it again simply increments it. The only checking of values before modifying them is when the rule is removed in SpecialOrders.SpecialOrder.RemoveSpecialRuleAtEndOfDay, it checks it is greater than 0 before decrementing; and in Game1._newDayAfterFade, it checks if the rule is not active and the difficulty is greater than 1 and drops it to 1.

As the skull cavern is effectively just deeper in the mineshaft, and uses mostly the same code, the effects will be quite similar.

The key code locations are:

• Monsters.Monster.InitializeForLocation - adds 0.1% chance to drop diamond or prismatic shard for each level of difficulty (adding from the base 0.1%)
• Locations.MineShaft.BuffMonsterIfNecessary which in turn calls monster.BuffForAdditionalDifficulty using the additional difficulty - increases damage, health and resilience.
• Locations.MineShaft.adjustLevelChances - increases chance for monster by 2% for each level, with the result still modified by other things (e.g. monster musk, desert festival, etc).
• Locations.MineShaft.createLitterObject - increases chance for radioactive ore by 0.1% for each level.
• Locations.MineShaft.populateLevel - Increases chance for spiders to have partners. The base value has 0.3 added for each level of difficulty, but it then checks 4 times, one for each direction. Also increases the chance for slimes to spawn as stacked slimes, by 10% for each level of difficulty, up to a hypothetical maximum of 50% if you somehow glitch out the value.

Then there are a bunch of other references which just checks as a binary toggle (>0, or <=0, depending on the location) JackBlack69 (talk) 20:31, 4 March 2026 (UTC)

Thank you for confirming! That was what I was seeing as well - always good to have another eye on it. I am working on an edit to the page now, as well as to the The Mines page. Doing my best to conform to the Wiki standards, but I'm new to it, so please be patient with me if any of the styling is off. ChloeCat (talk) 23:00, 4 March 2026 (UTC)

All done! Please let me know if there are issues. I'm happy to make the equivalent edits to The Mines page if everything looks good. ChloeCat (talk) 23:32, 4 March 2026 (UTC)

I made a couple of minor copyedits, but otherwise, I'm immensely grateful for the good job you did!

If you would like to update The Mines page, that would be great. Thank you! margotbean (talk) 18:11, 5 March 2026 (UTC)

Thank you!! :) I just updated The Mines. I tried to keep it consistent with the Skull Caverns page, including the copyedits you did. Looks like there were some stylistic aspects to the Wiki that I was not so familiar with - I appreciate you applying that consistency! I had a bit of trouble thinking of how to word the spider thing clearly and concisely, while not abbreviating it to the point of no longer being technically accurate. I know I personally get frustrated when there isn't clarity around how a percentage is being calculated and such (not necessarily on this Wiki specifically or anything - just in general), so I wanted to be precise. (Can you tell I work in mathematics? Lol!) But I figured people didn't necessarily need all the nitty gritty either. I ended up keeping it vague in the bulletpoints, and then describing it as best I could in the refs section where I point out the code. Please let me know if it seems unclear and I can try to reword a different way! Or if I've misinterpreted the code, certainly anyone is welcome to chime in! It seems like me and JackBlack are in agreement on things, so that's reassuring. :)

Also, if anyone wants to add Squid Kids as a possible monster to this page, that would be awesome. I'm not sure where to get the pngs for them (like if there's some official source we're supposed to grab from for consistency?). ChloeCat (talk) 01:02, 6 March 2026 (UTC)

It looks good. Thanks for putting in the details. I would have kept the buff monster thing as 1 reference instead of several, but that is more personal preference. As for the technical aspects of it, there are some parts which I think either aren't as clear as they could be, or may be slightly incorrect; but I'm not sure what the best way to word it is.

Firstly, for the spiders (leaper), I don't think it is worth mentioning the partner chance for 0 difficulty, as there should be no way for them to spawn. I have updated the wording for that.

For monster spawn chances, this is much more complicated. First, there are the additional factors which alter the chances, including the monster musk buff which multiplies it by 2; then there is the multiplication by ~0.66 if it is between levels 40 and 80 in the mines, or for skull cavern there is an additive and multiplicative amount for the calico statue effects. Then after that there is where it is actually used, where for each tile, it checks it is clear for a minable object, then checks if it should spawn a stone of some type (or similar), and then checks if there should be a monster; if it wasn't clear it instead does checks for barrels, then checks for monsters. So it is more complicated than a simple 2% increase, but I'm not sure what the best way to say it is.

Likewise, for the radioactive ore chance, it is increasing the chance for a stone to be radioactive ore.

For the buffing, it buffs based upon the difference between the difficulty and the base difficulty of the monster. Most monsters have a base difficulty of 0, but the putrid ghost, leaper (spider) and shooter (I think that is the shadow sniper near the bottom of the mines) instead have 1. This reduces how much it increases by, and means the level 1 difficulty version of these aren't buffed, and the level 2 versions are only buffed by one level, so the resilance is only multiplied by 2. Also, checking for this, there is one additional effect of this difficulty switch, which only effects the putrid ghost and shooter, at difficulty 1 they don't have the chance to drop galaxy souls or Qi gems (which is only checked if you have found at least 100 golden walnuts and killed at least 50 hard mode monsters), nor do they count towards hard mode monsters slain; but at difficulty level 2 they do.

I have added the dangerous squid kid to the table.

JackBlack69 (talk) 22:11, 6 March 2026 (UTC)

Please don't leave this for me to parse out, understand, and add to the wiki! margotbean (talk) 00:39, 7 March 2026 (UTC)

I was more leaning towards it's too complicated, so lets not put the exact numbers, and instead keep it more vague as "increases moster spawn rate" and at most have the ref say something like "Increases the base chance by 2%, which is then modified further by later stages of the algorithm". But wanted to see what ChloeCat said first. JackBlack69 (talk) 23:15, 7 March 2026 (UTC)

Great points! Thank you for adding squid kids, and for that spider change - you're right that since they don't spawn at danger level 0 anyway, it wasn't particularly helpful to point out the 30% partner chance that never actually applies lol. I was not aware that certain monsters had a higher base difficulty level - great catch! I can see that in the code now that you've pointed it out. I think I can reword the bullet nicely to account for that - let me give it a go. Also a nice catch on the galaxy soul / gem thing - I can add that too.

With the spawn chance increase, you're absolutely right that there are a ton of factors at play, but I do think it's true that there IS a 2% increase per difficulty level. Not positive on that, so please do correct me if I'm wrong. But it seems like that does come into play regardless of other factors, so I think it's okay since this section is only about the effects from difficulty levels - we aren't saying things like monster musk are no longer relevant. The multiplication by ~.66 from levels 40-80 in the mines is one of the flat toggle checks, so doesn't really belong in the bullet list (since it's described as "While this mainly acts as a toggle between the normal Skull Caverns (difficulty 0) and the "dangerous" Skull Caverns (difficulty > 0), there are some effects which stack"). I do think we should include it somewhere, though. Maybe a separate bullet list of the toggle effects that don't stack. That could help clean up the pages a bit too, especially The Mines - I noticed some of the effects of dangerous mode are a little bit scattered throughout the page. Might be better to have them in one bullet list like that. But basically, the 2% spawn chance increase still seems correct to me, although it might still be useful to add more details about other effects on that chance. What do you think?

Not sure how to better word the radioactive ore thing. Hmm. I'll think on it.

Most of the above is more directed at discussing code with JackBlack, but Margotbean, would love your opinion on if I were to reformat the Skull Cavern and The Mines pages a bit to make a bullet-point list of the toggled effects. As in, below the bullet list of effects that stack, I could make a list of "these are all the effects of being above difficulty level 0 that don't stack", like the monster spawn boost on specific floors and the changes in certain monsters' appearances. ChloeCat (talk) 01:22, 8 March 2026 (UTC)

Okay, did my best to express those shadow sniper, spider, and putrid ghost exceptions nicely. Let me know what you think. I also made a bug report on the forum - I imagine shadow snipers and putrid ghosts are meant to have the hardcoded dangerous monster status, like spiders do. ChloeCat (talk) 02:17, 8 March 2026 (UTC)

Went ahead and edited Monsters#Dangerous Monsters as well to note these changes. Btw, did not change Skull Cavern page about this stuff specifically since I don't think shadow snipers, spiders, or putrid ghosts spawn there anyway! ChloeCat (talk) 02:32, 8 March 2026 (UTC)

Firstly, while the number in the code does give a +2%, that isn't directly the chance to spawn the monster. the number itself is problematic because of stone spawning first. The stone spawning chance (ignoring modifications) is between 10 and 30%.

So if we ignore barrels and just focus on stone and monsters, that 2% chance is actually 2% of a chance between 70% and 90%. That gives a 1.4% to 1.8% chance increase per difficulty level. But if it isn't a valid spot for a stone, and barrels can't be added, then it is a 2% chance.

Then as well as that, there is also what it means to be that increase, where the current wording is vague. It isn't an overall chance for a monster to spawn, but a chance per square.

Onitially I thought this can be addressed as rewording to something more like "Chance of a Monster spawning on an empty square increased by 2% per difficulty level". But that is also problematic because monsters are checked before items, so it would need to be on a square that is not occupied by a stone, barrel or static ladder. But even that still isn't completely correct for 2 reasons, one is that after populating the level with everything else, the last thing to be added are ore clumps meaning there is a chance for that tile to have been a monster, but that check failed so it ended up as an ore clump.

But the other more complicated impact to both the wording and the number, is that after the main level population where it goes square by square, it checks if there are more than 35 stones, and if so does more complicated processing. For every 35 stones it will randomly try to get a stone from the list of objects on the level. If that random attempt succeeds, it then considers a square region around the stone (not quite centered on it, and with a side length of 2-6 squares with 2 being half as likely as the other options). It will iterate through that square and remove every stone there. In addition to removing the stone, if it is far enough away from the starting ladder, there is a 10% chance per region that it will try to spawn a mosnter there with a 12% to do so for a given tile it is iterating over giving a total chance of 1.2% per tile, with this entirely unaffected by difficulty.

This complicates the wording used, as now even saying an empty square doesn't work. e.g. if you have monsterChance and stoneChance artifically set to 1, for most levels you end up with large regions without anything, because there was originally a stone, and this last process wiped it out. Likewise, you can have the monsterChance set to 0 and still have monsters spawn because this process spawns monsters indpenendent of that chance.

And the idea of working out the overall chance and seeing how it changes it is far too complex as this is a simple check of 35 stones, meaning it depends on the level size and how many of those squares can have a stone.

Because of this I think it is much better to have the wording be "increases the average number of monsters spawned on each floor." or "Increase the chance of monsters spawning", with at most having a note in the reference that during the initial level population as it goes tile by tile it increases the chance for a monster to spawn on a tile that is not a stone or ladder by 2%, which is also affected by other factors that affect monster spawning rates. JackBlack69 (talk) 22:04, 11 March 2026 (UTC)

Ooh, very interesting analysis! Since I hadn't looked at Stardew's code before this, I was unaware of all those additional factors. Totally see what you're saying now. Thanks for laying it all out! I do agree with you about putting the less specific wording, given the complicated spawning mechanics. Personally I like the idea of having the reference note, and then the subset of people who are curious to hear more about the "additional factors" or however it's worded might think to check the talk page and can read this more detailed discussion! ChloeCat (talk) 20:41, 12 March 2026 (UTC)

Special floor spawns

While looking through the code for some slimes, I found something I had never noticed before. In MineShaft.getMonsterForThisLevel after first checking for dino areas and dark areas (mummy floors), the next check is if (this.mineLevel % 20 == 0 && distanceFromLadder > 10f). This means any floor that is a multiple of 20, that is not an infested or dino or mummy floor, will only have bats spawning far from the ladder, i.e. the only non-bat monsters spawning will be close to the ladder. Then further down it checks if (this.mineLevel % 16 == 0 && !this.mustKillAllMonstersToAdvance()), so any floor that is 8 more than a multiple of 16 (as 120 is 16*8 - 8 and this is using level, not skull cavern level), which is not an infested or dino or mummy floor, will only have bugs.

Is this worth adding to the page? If so, where would be a good spot for it?JackBlack69 (talk) 19:41, 12 March 2026 (UTC)

Ooh, obviously Margotbeans would be the one to answer whether this should be added and where, but I just wanted to jump in to say thanks for pointing this out! Really interesting! I have definitely noticed those sorts of phenomena in passing just by playing a lot of Skull Caverns, but not enough to notice specific patterns or determine if it was anything other than coincidence. Very cool! ChloeCat (talk) 20:44, 12 March 2026 (UTC)

It feels like implementation details that are too much for the average user. Probably too much for anyone not equipped to read the source code themselves. margotbean (talk) 17:30, 13 March 2026 (UTC)