Minecraft Wiki

Slimes attacking other mobs now?[]

The trivia section mentions that slimes will only attack players. However, I am observing that large slimes appear to be attacking iron golems as of 1.8. Can anyone verify if the trivia section needs to be updated? 22:17, 7 April 2015 (UTC)

Verified for 1.11.2, Magma Cubes, too Torzod (talk) 19:56, 19 March 2017 (UTC)


The trivia section says that slimes do not prevent you from sleeping. This is suspicious, and possibly a hoax. Please attempt to verify this. 02:01, 7 May 2015 (UTC)

Verified. Ghasts too, and most likely Magma Cubes. The code checks for the "mob" base class, but Slimes and Ghasts don't extend this class. Anomie x (talk) 10:32, 7 May 2015 (UTC)

Big slime required spawning space[]

On the wiki page it says that big slimes need only a 2,5 block high space to spawn in, however the minecraft forum thread that is used as a source claims that this is 3 blocks. Many tutorials on youtube also stick to 3 blocks high when it comes to spawning big slimes. Which is correct?

Herkio (talk) 00:38, 16 December 2015 (UTC)

Leasoncre (talk) 09:51, 20 January 2016 (UTC) tested in 1.8 flat world, big slime requires 2.5 vertical air blocks to spawn

Verify information[]

Anomie x or someone else with knowledge of the code, would you be able to confirm the information in this article, especially what is marked with a verify tag? Many thanks. GoandgooTalk
07:56, 20 January 2016 (UTC)

Of the stuff marked with "verify", checked in 1.8.8:
  • At the same time they fixed stuff like wither skeletons not spawning in 2-high spaces, they presumably fixed slimes. The bounding box requirement is just that the bounding box of the mob-to-be-spawned doesn't intersect any entities, block bounding boxes, or liquids (this is separate from the other checks described in Spawning#Spawn conditions). The slime's size is correctly described under Slime#Behavior: "its dimensions are 0.51 blocks times its size in each dimension", and since the mobs spawn at (X.5, Y.0, Z.5) the figures later in the paragraph are generally correct but leave out that a partial block like a ladder on the far side of one of the edge blocks won't stop the mob from spawning there.
  • As for the AI, the slime has four "routines": float, attack, move (MCP calls it "face random"), and nothing (MCP calls it "hop").
    • "Float" makes the slime swim when in water or lava, by having it jump with an 80% chance per tick.
    • "Attack" makes the slime try to attack its target for 300 ticks (or until it no longer has a living target). Targets (players or iron golems) are found as usual, using the generic.followRange attribute which for slimes is 16 plus a random bonus of 0–5%.
    • "Move" makes the slime jump in a random direction when it's on the ground, not in water or lava, and has no attack target. It picks a new random direction every 40–99 ticks of the AI routine (but note the routine won't tick while the slime is in the air after jumping). There is no limit on the angle by which the direction changes.
    • "Nothing" takes effect when all of the above don't apply (i.e. it's in the air and has no target), and doesn't do anything interesting.
    • Also of note is that the slime will wait on the 10–29 ticks after landing from a movement-hop or 3–9 ticks after landing from an attack hop (i.e. the article is more or less correct on that point). This is done by the movement code itself, it just ignores the AI routines saying "jump" for the specified number of ticks.
      • And magma cubes have 4 times the delay: 40–116 ticks for a movement-hop or 12–36 ticks for an attack hop.
  • It is correct that slimes will still move when no players are nearby. The usual stopping is done by the random-wander AI routine just refusing to run, which slimes don't use.
  • The slime's jump distance isn't directly controlled by the size. The generic.movementSpeed is 0.2 + 0.1 * size, and that affects how fast it moves while jumping, which affects the distance.
  • The bit about most mobs (specifically the ones that use the generic "attack on collide" AI routine) attacking at a rate of 1 attack per second is true. These mobs also only attack their target on collision. But slimes attack any player or iron golem they collide with on every collision regardless of time elapsed or whether they're actually targeting the attacked mob; mercy invulnerability limits it to 1 actual hit per half-second per entity.
    • You could theorize that most mobs' attacks are a punch or bite or whatever, while slimes are some kind of acid that hurts anything they bump into. There is, of course, no support for that in the game beyond the mechanics of how the different mobs' attacks function.
  • Slimes jump the same as all mobs when jumping (initial upward velocity is 0.42 normally, and 0.04 when in lava). Magma cubes, on the other hand, jump higher depending on their size (initial upward velocity is 0.42 + size * 0.1 normally, and 0.22 + size * 0.05 when in lava).
  • Other magma cube differences from slimes: immune to fire, armor is 3× slime's, their render brightness is not affected by external light level, they have "flame" particles instead of "slime" particles, they drop magma cream as described in magma cube rather than slime balls, there's something MCP calls a "squish amount" that gets adjusted differently, magma cubes completely ignore falling (no damage, no fall-damage sound, no footfall sound, no ground particles, no damage to ridden entities either; but note slimes get special sound and particles from a different mechanism that magma cubes still apply), even the tiny size can deal damage, attack strength is slime's + 2, different sound events, always makes a slime sound when landing (normal slimes only do it for size 3+).
HTH. Anomie x (talk) 14:33, 20 January 2016 (UTC)
Wow, thanks for all the information that you've found on the slimes. Would you be able to update the article accordingly and perhaps add some of this information which is not currently in the article? Or perhaps if some of it is too detailed it could perhaps be added to the tutorial article. GoandgooTalk
01:01, 21 January 2016 (UTC)
Anomie x? GoandgooTalk
01:56, 6 February 2016 (UTC)
It might be better for someone else to do the writing. Anomie x (talk) 12:51, 6 February 2016 (UTC)
KnightMiner? Perhaps you could help remove the verify tags and add some of Anomie x's info? GoandgooTalk
01:44, 7 February 2016 (UTC)
I can try to work it into the article, though with the amount of information here I most likely won't have enough time until Monday. KnightMiner t/c 03:42, 7 February 2016 (UTC)

Global height limitation on spawning[]

So as I was playing around with commands and mob spawners I noticed that a slime mob spawner will not spawn moms on the surface, it seems only at the Y positions it would if it were a slime chunk. -- 19:00, 8 February 2016 (UTC)

Slimeballs in PE[]

The history section does not tell when slimes started dropping slimeballs, and the slimeball page doesn't indicate this either. In 0.9.0, slimeballs existed, but they could only be obtained using inventory editing. Does anyone know when slimes first dropped slimeballs? The BlobsPaper.png 04:30, 16 January 2017 (UTC)

Confirmed they can climb ladders[]

Community members on the Discord server tested it on Java & Bedrock. Slimes can climb ladders. --HelenAngel (talk) 00:40, 14 November 2017 (UTC)

Maximum Spawning Level[]

If the maximum spawning height level is 40 and I build a platform at height level 39 will Slime spawn on that platform? T1Cybernetic (talk) 19:51, 13 February 2018 (UTC)

Responsive edit - please note, you did not read the wiki properly. the wiki says below level 40. this means that the slime will spawn below level 40. In order to spawn below 40 the block has to be at 38, then the slime spawns on 39, which is below 40. it is resting, standing, walking, jumping on the block occupying 38, which means it is on 39. –Preceding unsigned comment was added by (talk) at 1:19, 05 November 2019 (UTC). Please sign your posts with ~~~~

I don't know where to ask this, but I have the same question. The page says that slimes spawn "below layer 40". When I stand on my highest platfrom, debug screen says: "XYZ: ... 40 ..." and when I look at the spawning platform F3 says "Looking at: ... 39 ...". I would say that such platfrom is below layer 40 (y of the platform is 39). Is this true? Will the slimes spawn on this layer? 23:18, 17 April 2018 (UTC)

They will, assuming you are in a slime chunk or swamp biome though. jjlr (talk) 23:42, 17 April 2018 (UTC)
Thanks. I am in a slime chunk. I am not so sure. Now I've opened a copy of my world in the MCEdit, deleted everything except one/highest spawning platform (16x16) and put fences all around and also through the middle of the platform. I made a 6 blocks wide part with "XYZ: ... 39 ..." and "Looking at: ... 38 ..." and the rest - 9 blocks wide part with "XYZ: ... 40 ..." and "Looking at: ... 39 ...". And I see slimes spawning only in the smaller 6 blocks wide part that is one block lower, and absolutely no spawns in the larger part. 17:19, 18 April 2018 (UTC)
Someone else had the same question in 2012 :) And he came to the same conclusion as I have - slimes spawn only on layer 38 and below ("below layer 39") - that is feet level has to be 39 ("XYZ: ... 39 ...") and if you look at the spawn block you get "Looking at: ... 38 ...". 17:31, 18 April 2018 (UTC)
The air block they spawn in must be below level 40. If the floor is at 39, the air block on top is at level 40, thus they cannot spawn in it. - Princess Nightmoon (TalkContributions) 17:37, 18 April 2018 (UTC)
Wow. This solves the mystery. Thanks! 16:47, 19 April 2018 (UTC)

Beta 1.2 texture change[]

I looked at my version files for Alpha v1.0.14 and Beta 1.2 and I found that the textures are the same for both versions. I am led to believe that this part of the History is inaccurate. tangeruse 21:12, 17 November 2018 (UTC)

You're right. I summoned a Slime at Alpha 1.0.16 and it looks the same as in Beta 1.2. RosilloGames (talk) 18:58, 19 April 2020 (UTC)

What's the difference between Slime's size and it's Size NBT tag?[]

The page haven't mentioned any about that. As a reader, I would be confused.

‘size 1 to 256 (NBT Size tag 0–255).’ Why not use the Size in NBT uniformly?--kaniol TC 15:16, 6 August 2019 (UTC)

Slimes look friendly, but they are hostiles.[]

Beginners get confused from this. -- 16:15, 16 March 2020 (UTC)

False information in history[]

It says Slimes drop 0-2 slimeballs only from beta 1.2_01, however they dropped 0-2 slimeballs since they were added in alpha 1.0.11 (Here a video as a proof https://www.youtube.com/watch?v=oY0FY_y3cDs (sound warning))

-This video refers to a minecraft Java Edition Alpha 1.0.11 version, but the "Verify" tag is linked to the Pocket Edition 0.12.1. Do we talk about the same problem or was the tag put in the wrong place?

--Melee33 (talk) 17:05, 19 May 2020 (UTC)

A question about slimes spawning within slime chunks[]

They can't still spawn on transparent blocks like slabs and glass, can they? --Lapsem (talk) 07:19, 21 July 2020 (UTC)

Referencing another game[]

In "Trivia" it states that slimes may be a reference to Gloople and Oozle from Amorphous+, though slimes are predated by Amorphous+ I do not believe this is a case as Glooples are normally found as, well, Glooples, and only INCREASE in size (by merging with other Glooples, into an Oozle)

It's speculation. I removed it. Amatulic (talk) 03:43, 8 December 2020 (UTC)


Hi, I was listening to the sounds and some of the sounds matched the sounds that play when you walk on slime in education edition, can somebody fix that? -MissBananaPants59234--MissBananaPants59234 (talk) 21:11, 7 May 2021 (UTC)

Reverted edit: was needed[]

The phrase I added was needed and should not have been reverted. It clarified an important point, and the excuse used by the person who reverted it "50-70" means "around the surface" is obviously incorrect. It has to be ON the surface.

I would like my edit put back, but I can't figure out how to do it, nor do I know what the "revert wars" policy is on this wiki. Can we please have some discussion about this? SirDaddicus (talk) 14:23, 17 May 2021 (UTC)

If I don't hear any objections, I'll be re-adding the phrase near the end of this week. SirDaddicus (talk) 13:42, 18 May 2021 (UTC)

Slimes do not spawn near the surface, they spawn between 50-70 in their code. There is no check that those levels are surface in the code, so saying they spawn on the surface is misleading (notably in amplified worlds).
That said, it is nice to tell the user 50-70 is typically the surface as not everyone has common elevations memorized. I think different wording may be appropriate, such as saying they spawn "50-70 which is typically near the surface"
Regarding revert war policy, we don't have an official policy. Reverting an edit that is reverted is generally fine if you have good reason, reverting an edit 3 times is the rule of thumb for a revert war. KnightMiner (t/c) 19:14, 18 May 2021 (UTC)
Thank you! I was kind of wondering about whether they could spawn in caves near the surface (that opened to the surface), i.e. whether open caves "count" as the surface.
However, I did do some extensive testing to see whether they would spawn in an (enclosed) underground location. I built it at level 51 and spent several real-time days (all at full-moon) 25 blocks away, but never saw a slime spawn.
Has anybody ever actually seen a slime spawn underground (but above layer 50) in a swamp biome? SirDaddicus (talk) 21:38, 19 May 2021 (UTC)
In Bedrock Edition I have seen slimes spawn on the surface in swamp biomes during a full moon. And I have seem slimes spawn below level 40 in slime chunks. I can't say I've ever seen one spawn underground above level 50 in a swamp biome, but I generally have not been underground in a swamp biome. KnightMiner's suggestion of mentioning that 50=70 is typically near the surface is a good one. Amatulic (talk) 01:18, 19 May 2021 (UTC)
I added KnightMiner's excellent suggestion as a parenthetical note at the end of that paragraph. If anybody doesn't like the wording, please feel free to tweak or add to this section of the talk page. Otherwise, I think we can call this discussion complete!
Thank you all for your edits and suggestions! SirDaddicus (talk) 21:58, 19 May 2021 (UTC)

Slime Chunk calculations[]

See below for the full algorithm as displayed on the main page.

I would like some help interpreting the math in this function. I don't know how to program in Java, so many of the constructs are foreign to me. I'll list my questions in the order things appear in the code:

  • Does the "L" at the end of the number on the "long seed =" line mean "long"?
    • Does that mean long integer or long real number?
  • On the same line, can I assume that 12345L is a fake seed for illustration purposes?
    • Same question for the x and z position variables.
  • Are xPosition and zPosition world coordinates, or chunk coordinates (i.e. divided by 16 and rounded down)?
  • What algorithm does the Random rnd = line use? (This is the most important question, for without it, the rest are useless to a non-Java programmer.)
  • In the last line, what does rnd.nextInt(10) do? (My guess is some kind of modulo function.)

Thank you!

   import java.util.Random; 
   public class checkSlimechunk{ 
       public static void main(String args[]) 
           // the seed from /seed as a 64bit long literal
           long seed = 12345L;
           int xPosition = 123;
           int zPosition = 456;
           Random rnd = new Random(
                   seed +
                   (int) (xPosition * xPosition * 0x4c1906) +
                   (int) (xPosition * 0x5ac0db) +
                   (int) (zPosition * zPosition) * 0x4307a7L +
                   (int) (zPosition * 0x5f24f) ^ 0x3ad8025fL
           System.out.println(rnd.nextInt(10) == 0);

Answer(s) The longs and ints at the start are indeed examples. "Random rnd = ..." does not use an algorithm yet. It just sets the initial seed for the Random object to start generation pseudo-random values out of.

   Random rnd = new Random( chunkSpecificSeed );

is equivalent to

   Random rnd = new Random();
   rnd.setSeed( chunkSpecificSeed );

"rnd.nextInt(10)" is what actually generates a random integer based on the seed that the Random object was set to.

You should be able to find the rest of your answers here: https://docs.oracle.com/javase/8/docs/api/java/util/Random.html

About the page image[]

What program was used to create the semi-transparent slime image?

Slime chunk light level MC 1.18+[]

I've read several claims online saying that, along with the light levels of other mobs spawning in MC 1.18 being lowered to 0, the light levels of Slimes spawning in slime chunks has been lowered to 7 or lower.

However, when I load up a default Superflat world (Biome = Plains), slimes still seem to be spawning in daylight basically everywhere even though the light level (sky) is much higher than 7. The same seems to be true if I cover the whole flat world with torches. So it's not a question of block light versus sky light. So unless a flat world has a unique property that lets Slimes spawn in higher light levels, I am going to call this claim that "Slimes need a light level lower than 8 in slime chunks" bogus for now.

I thought this observation and information were more fitting for the talk section of this page than for the main article. I may follow up with some more info. – Unsigned comment added by Robijnvogel (talkcontribs) at 10:56, 2 January 2022‎ (UTC). Sign comments with ~~~~

Your observations may be true for Java Edition (is that what you use?), but it doesn't match my observation for Bedrock Edition. Since 1.18, my slime farm that occupies two adjacent slime chunks no longer works, and neither does a cave in another slime chunk that I lit up. Both used to produce plenty of slimes. Now, nothing. I need to reduce the light level in my farm (which will be a big job as it involves a lot of aerial construction to get at the torches) to see if light level less than 7 works. Amatulic (talk) 23:12, 11 January 2022 (UTC)
OK, I verified that slimes spawn in full daylight in a flat world (on which the surface is at y=4 in Bedrock Edition). That means that the slime chunk generation algorithm has changed for Bedrock Edition. That's the only explanation I have for my prior slime-producing areas no longer working. Amatulic (talk) 20:13, 19 January 2022 (UTC)

Slimes still spawn at Y < 40 in 1.18[]

That means: a slime can spawn on solid blocks, that are at y = 38 or less.

Tested (again) in singleplayer, v1.18.1

This is same as in previous versions. Only the sentence "slimes spawn at y<40" might be misunderstood too easily. 17:41, 19 January 2022 (UTC)

It seems to me that would be y=39 or less, which would still allow the smallest-size slimes to spawn. The requirement y<40 makes perfect sense. Amatulic (talk) 20:15, 19 January 2022 (UTC)