Mob Grinding Utils is a Minecraft mod that gives you the blocks to build proper mob farms, rather than one machine that does everything for you. There’s a block to push mobs around, a couple of ways to kill them, a hopper that picks up the drops and the XP, and tanks that store that XP as a liquid so you can use it later.
It goes further than killing though, as you can change what spawns with 
Dreadful Dirt and 
Delightful Dirt, turn a Chicken into a Spawn Egg for any mob, and run an 
Entity Spawner off the XP your farm makes. This guide covers every block in the mod, how to power them, and how they fit together into a mob farm that runs itself.
Getting Started with Iron Spikes
The first thing most people make is a row of 
Iron Spikes, as they’re cheap and they don’t need any redstone to work. They’re made from three 
Iron Swords and a 
Block of Iron, and anything that walks into them or falls onto them takes damage for as long as it stays there.
Each hit does 5 damage, which is two and a half hearts, and it goes straight through armor, so a Zombie in a full set of Iron armor dies just as quickly as one without. Iron Spikes also make the mob drop its XP when they kill it, which is something that doesn’t normally happen with mobs killed by the environment.
The catch is that a mob killed by Iron Spikes doesn’t count as a player kill. That means you won’t get the drops that only come from a player killing the mob, and Looting won’t do anything, so if you want those drops you’ll need to move on to the 
Mob Masher, which is covered further down.
Absorption Hopper
The 
Absorption Hopper is what collects everything your farm kills, and it picks up both the items and the XP orbs in a 7x7x7 area around it. It doesn’t need to be powered, so as soon as it’s placed it’ll start pulling in anything that drops nearby, which makes it the block you’ll build the rest of the farm around.
Inside its GUI there’s a button for each side, and each one can push out items, push out fluid, or do nothing. Items go into whatever inventory is on that side, like a Chest, and the XP it picks up is turned into Fluid XP that it pushes into a tank. It has a small 16 bucket tank of its own for when nothing’s attached yet.
Each 
Absorption Radius Upgrade makes the area one block bigger in every direction, and you can fit six of them, which takes it all the way up to 19x19x19. The area can also be moved in the GUI with the offset buttons, and there’s a button to show the area, which is really useful for checking it actually covers where your mobs are dying.
There isn’t an item filter on the Absorption Hopper in this version, which is something a lot of people go looking for. If you only want to keep certain drops, push everything into a Chest or a storage mod and sort it out from there, or send the junk into a Hopper that feeds a trash can from another mod.
Singularity Tanks and Fluid XP
The XP your farm collects gets stored as Fluid XP, and every point of experience is worth 20 millibuckets of it, so a full bucket holds 50 points. The 
Singularity Tank is the basic tank for it, made from four 
Iron Ingots and five 
Glass, and it holds 32 buckets of any liquid, not just XP.
There are two other tanks as well, and they all store their fluid when you break them, so you can pick up a full tank and move it without losing anything. If you ever want to empty one, put it in a Crafting Table on its own and it’ll come back out empty, which works for all three of them.
| Tank | Holds | What It Does |
|---|---|---|
| Singularity Tank | 32 buckets | Stores any liquid, including Fluid XP |
| XP Drain Singularity Tank | 32 buckets | Drains the XP of any player standing on top of it |
| Jumbo Tank | 1,024 buckets | A much bigger Singularity Tank, made from four of them |
The 
XP Drain Singularity Tank is handy for banking your own levels before you do something risky, as you just stand on top of it and it pulls your XP out a point at a time. The 
Jumbo Tank is for once your farm is running all the time, as 32 buckets fills up quicker than you’d think with a good farm running.
Getting the XP Back Out
The simplest way to get your XP back out of a tank is the 
XP Tap, which you place on the side of a tank and right-click to open. It’ll spray the Fluid XP back out as orbs until you close it again or the tank runs dry, and it works on all three of the tanks.
You can also right-click a tank with a 
Glass Bottle to fill it with a 
Bottle o’ Enchanting, which takes 200 millibuckets each time and is a nice way to carry XP around with you. A 
Bucket works on any of the tanks too, and a 
Fluid XP Bucket is something you’ll need for a lot of the recipes further down, so it’s worth keeping a few filled.
Mob Fan and Entity Conveyor
The 
Mob Fan pushes mobs in whichever direction it’s facing, so it’s how you move them from where they spawn to where they die. It needs a redstone signal to run, so put a Lever or a 
Block of Redstone next to it, and you’ll see the blades start to spin once it’s switched on.
By default it pushes about five blocks, and anything in the way that’s solid stops the air, so keep the path clear. A fan facing upward will lift mobs, and it also resets their fall distance, which means they won’t take any fall damage while it’s holding them, so don’t use one pointing up if you’re relying on a drop to kill them.
There are three upgrades for the Mob Fan, and they all go into its GUI. You can see the area it covers in the same GUI, which makes it a lot easier to line the fan up with the room you’ve built, rather than guessing and watching mobs get stuck in the corners.
| Upgrade | Adds | Max |
|---|---|---|
| Mob Fan Width Upgrade | 1 block on each side | 3 |
| Mob Fan Height Upgrade | 1 block on each side | 3 |
| Mob Fan Distance Upgrade | 1 block of reach | 10 |
If your Mob Fan isn’t working, it’s nearly always the redstone, as it won’t do anything without a signal even though it looks finished. The other thing to check is that nothing solid is sitting in front of it, as that cuts the reach short, and that the mobs are actually inside the area that the GUI shows.
Entity Conveyor
The 
Entity Conveyor moves mobs and items along it in a straight line, and one craft gives you six of them. They’re placed so they carry things back toward you, and mobs can spawn on them, so you can use them as the floor of a spawning room and have everything that spawns carried straight off to the killing area.
6If you need to walk across a line of them yourself, just sneak, as sneaking stops them from moving you. They’re a good match for the Mob Fan, as the fan can push mobs onto the start of the conveyor and the conveyor can take them the rest of the way to the Mob Masher or the spikes.
Mob Masher
The Mob Masher is the main killing block in the mod, and it’s the one to use once you’ve outgrown Iron Spikes. Anything that kills with it counts as a player kill, so the mobs drop the same things they’d drop if you’d killed them yourself, and it can be upgraded with the same enchantments you’d put on a sword.
It’s made from two Iron Swords, three 
Diamonds, two Iron Spikes, a Block of Iron and a Block of Redstone, so it’s quite a bit more expensive than the spikes. You’ll want one anyway though, as it hits a lot harder, and it’s the only way to get player-kill drops and mob heads out of a farm without standing there yourself.
How to Use and Power the Mob Masher
The Mob Masher needs a redstone signal to run, the same as the Mob Fan, and without one it won’t hit anything. Once it’s powered, it attacks every mob that’s inside the Mob Masher’s own block twice a second, so you need to push mobs into the block itself, not just up against the side of it.
That also goes for you, as it’ll happily hit a player standing in it just like it hits a mob, so don’t walk into one while it’s switched on. A common way to set it up is a Mob Fan pushing mobs down a short corridor that ends in the Mob Masher, with an Absorption Hopper underneath or next to it to pick everything up.
If your Mob Masher isn’t working, check the redstone first, as it needs a signal the whole time it’s running. After that, check the mobs are really getting inside the block, as a mob pressed against the outside won’t get hit, and the Mob Masher doesn’t reach out into the blocks around it.
Mob Masher Upgrades
The Mob Masher has six upgrades, and you can put up to ten of each one into it. They’re all crafted with 
Gold Nuggets and 
Redstone Dust, plus one item that matches the enchantment, like Iron Swords for Sharpness or 
Lapis Lazuli for Looting, so they’re cheap to make once you’ve got some Gold.
Sharpness, Smite and Bane of Arthropods are much stronger on the Mob Masher than on a sword, as every upgrade adds ten levels of the enchantment rather than one. Looting and Fire Aspect only add a single level each, but ten Looting upgrades still gives you Looting X, which is a huge amount of extra drops.
| Upgrade | Each One Adds | With 10 |
|---|---|---|
| Mob Masher Upgrade Sharpness | 10 levels of Sharpness | Sharpness 100 |
| Mob Masher Upgrade Looting | 1 level of Looting | Looting X |
| Mob Masher Upgrade Fire | 1 level of Fire Aspect | Fire Aspect X |
| Mob Masher Upgrade Smite | 10 levels of Smite | Smite 100 |
| Mob Masher Upgrade Arthropods | 10 levels of Bane of Arthropods | Bane of Arthropods 100 |
| Mob Masher Upgrade Beheading | 10% chance of a head | A head every kill |
Fire Aspect is the one to be careful with, as it cooks any meat the mobs drop, which is great for a Cow farm but not something you want if you’re after the raw drops for anything else. Zombies hit by the Mob Masher also can’t call in other Zombies to help, so they won’t flood the farm.
Beheading and Mob Heads
The 
Mob Masher Upgrade Beheading gives a 10% chance of the mob dropping its head per upgrade, so with ten in it you’ll get a head from every kill. It works on Zombies, Skeletons, Creepers, Wither Skeletons and the Ender Dragon, and it’ll also take the head of a player if one happens to wander in.
| Mob | Head |
|---|---|
| Zombie | Zombie Head |
| Skeleton | Skeleton Skull |
| Creeper | Creeper Head |
| Wither Skeleton | Wither Skeleton Skull |
| Ender Dragon | Dragon Head |
| Player | Player Head |
A Wither Skeleton farm with a fully upgraded Mob Masher is the easy way to get enough 
Wither Skeleton Skulls to summon the Wither as many times as you like. If Tinkers’ Construct is installed as well, Beheading also works on Blazes, Endermen, Spiders, Piglins and a few others, and drops the heads that Tinkers adds.
How to Get a Rotten Egg and Dreadful Dirt
Dreadful Dirt is a block that spawns hostile mobs much faster than normal, and it’s what a lot of people use in place of a dark room full of empty space. You can’t craft it though, as it comes from a 
Rotten Egg, and the Rotten Egg comes from feeding a Chicken some 
GM Chicken Feed Cursed.
Craft GM Chicken Feed Cursed
Four buckets of Fluid XP and five mob drops
The feed needs four Fluid XP Buckets in the corners, with a 
Spider Eye, some 
Rotten Flesh, any Seeds, 
Bones and 
Gunpowder in the rest of the grid. The Fluid XP is the part that stops most people, so you’ll need a tank with some XP in it first, even if it’s only from a simple Iron Spikes setup.
It’s the same recipe every time, so once you’ve got a tank of Fluid XP going you can make a few at once and keep them for later. Each one only makes a single Rotten Egg though, so you’ll need a feed and a Chicken for every 5×5 patch you want.
Feed it to a Chicken
It floats up and pops
Right-click an adult Chicken with the feed and it’ll start floating up into the air. After a second or so it pops, leaving behind a Rotten Egg and a few 
Feathers, and the Chicken is gone, so you’ll need a Chicken for every egg you want. Baby Chickens won’t take the feed, so it has to be a fully grown one.
Use the Rotten Egg on the ground
Turns a 5×5 area into Dreadful Dirt
Right-click a 
Grass Block, 
Dirt, 
Mycelium or 
Farmland with the Rotten Egg and it’ll turn a 5×5 area around it into Dreadful Dirt. Only those four blocks get changed, and only on the same level as the one you clicked, so flatten the area out first if you want the full 25 blocks.
How Dreadful Dirt Works
Dreadful Dirt only spawns mobs when the light level above it is below 5, so it needs to be somewhere dark, and 
Tinted Glass is useful here as you can see in without letting any light through. Every block in the patch gets its own chance to spawn a monster, picked from whatever normally spawns in that biome, so a full 5×5 patch keeps a steady stream of them coming.
It stops once there are eight hostile mobs within five blocks of it, so you need to keep moving them off it, which is where the Mob Fan and the Entity Conveyor come in. If Dreadful Dirt can see the sky during the day it’ll set fire to whatever’s on top of it, so keep it covered, as it doesn’t work in daylight anyway.
Golden Egg and Delightful Dirt
Delightful Dirt is the peaceful version of Dreadful Dirt, and it spawns animals instead of monsters. You get it the same way, by feeding a Chicken, but this time it’s 
Nutritious Chicken Feed, which gives you a 
Golden Egg that turns a 5×5 area of Grass Blocks or Dirt into Delightful Dirt.
The recipe uses four Fluid XP Buckets again, along with a 
Carrot, a 
Potato, some Seeds, 
Wheat and a 
Beetroot. Everything except the Fluid XP comes from a normal crop farm, so if you’ve got the XP stored, it’s an easy one to make a few of at once.
Delightful Dirt needs a light level of 10 or more above it, the opposite of Dreadful Dirt, and it spawns whatever animals normally spawn in that biome, so build your farm in a Plains if you want Cows, Pigs, Sheep and Chickens. It also grows Grass and flowers on top of itself while it’s running.
In caves and rivers it uses the Plains animals, but it won’t work at all in oceans or in biomes that don’t have any passive mobs. If it can see the sky at night it’ll put Snow on top of itself, and it stops spawning once there are eight animals near it, so you’ll need to keep moving them along.
Entity Spawner and Spawn Eggs
The Entity Spawner spawns any mob you have a Spawn Egg for, and it’s fuelled by the XP your farm makes. It’s made from three 
Eyes of Ender, two 
Solid XP blocks, a Block of Redstone, two Blocks of Iron and a 
Piston, and like most of the other machines it needs a redstone signal to run.
Put a Spawn Egg in the top slot and 
XP Jelly Babies in the fuel slot, and it’ll spawn one of that mob every five seconds, using one Jelly Baby each time. The Spawn Egg isn’t used up, so one egg lasts forever, and it spawns the mobs in a 3×3 area around the Entity Spawner that you can see and move in its GUI.
Entity Spawner Upgrades
The 
XP Speed Upgrade makes it spawn faster, and with the full five in it, it’ll spawn a mob every second or so. The 
Entity Spawner Width Upgrade and 
Entity Spawner Height Upgrade each make the area a block bigger on every side, and you can fit five of each, which gives a lot more room for mobs to land.
Every mob still costs one Jelly Baby however fast it’s running, so the speed upgrades just use your fuel up quicker. Build the XP side of your farm first if you can, so that the Entity Spawner can feed itself off the XP from the mobs it spawns.
Why Your Entity Spawner Isn’t Spawning
A lot of people think the Entity Spawner needs darkness, but it doesn’t check the light level at all. What it needs is a redstone signal, a Spawn Egg, some Jelly Babies, and space in its area where the mob can stand, which means a solid block underneath and enough room for the mob to fit.
Light does still matter for what happens after the mob spawns though. Zombies and Skeletons spawned in the open during the day will catch fire, so it’s worth putting a roof over the area, and Tinted Glass is a good choice if you still want to be able to see in.
Getting Spawn Eggs with a Mob Swab
You can’t craft Spawn Eggs directly, but you can get one for nearly any mob with a 
Mob Swab. Right-click a mob with the Swab to collect its DNA, then craft the used Swab with any Seeds and a Fluid XP Bucket to make 
GM Chicken Feed for that mob.
Feed that to an adult Chicken and it’ll float up and pop, the same as with the eggs, but this time it drops a Spawn Egg for the mob you swabbed. It works on almost anything, apart from players, the Wither and the Ender Dragon, so it’s how you get eggs for mobs that are hard to find, like Blazes or Wither Skeletons.
XP Solidifier and XP Jelly Babies
The 
XP Solidifier turns Fluid XP into XP Jelly Babies, which are what the Entity Spawner runs on, and you can eat them too. It has its own tank for Fluid XP, so you can pipe XP into it from your tanks or just empty buckets into it by hand, and it doesn’t need any redstone.
It also needs an 
XP Mould Blank to work, made from eight Gold Nuggets around a Fluid XP Bucket. Put the blank in a Crafting Table on its own to turn it into an 
XP Mould Jelly Baby, then put that in the Solidifier, where it can stay, as it isn’t used up.
Each Jelly Baby takes one bucket of Fluid XP and five seconds to make, and XP Speed Upgrades speed that up, with room for nine of them in the XP Solidifier. It can push the Jelly Babies out to one side on its own, which you set in its GUI, so point it at a Chest or at a Hopper that feeds your Entity Spawner.
A Jelly Baby is worth 50 points of XP when you eat it, and if you sneak while you eat one from a stack, you’ll eat the whole stack in one go. Nine of them craft into a block of Solid XP, which is very bouncy and is also part of the Entity Spawner recipe, and you can craft the block back into nine Jelly Babies.
Wither and Ender Dragon Farming
Mob Grinding Utils has a few blocks aimed at farming bosses, and the most useful is Tinted Glass. It’s a lot cheaper than the vanilla version, as five 
Coal and four Glass make four of it, and on top of blocking light, the Wither can’t break it, which makes it great for building a cage to fight or farm the Wither in.
4It isn’t just the glass either, as every block in the mod is safe from both the Wither and the Ender Dragon. That means a Mob Masher, an Absorption Hopper and a tank can all sit right next to a Wither without getting blown up, which is how the bigger automated Wither farms are built.
The 
Wither Boss Death Muffler and the 
Ender Dragon Death Muffler stop the loud death sounds of the Wither within 8 blocks and the Ender Dragon within 32 blocks. You can also right-click either one to hide the boss bars, which gets rid of the pile of bars at the top of the screen when you’re killing lots of them.
The 
Ender Inhibitor stops anything within 8 blocks of it from teleporting, which is mostly for Endermen, as they’ll normally teleport straight out of a farm when they get hurt. It can go on any side of a solid block, and you right-click it to switch it on and off, so it’s easy to use in an Enderman farm in the End.
How to Set Up a Simple Mob Farm
Putting it all together, a basic mob farm with this mod only needs a few of the blocks, and you can add the rest later. The idea is to spawn mobs on Dreadful Dirt, push them into a Mob Masher with a Mob Fan, and collect everything with an Absorption Hopper that feeds a Chest and a tank.
Build a dark spawning room
Dreadful Dirt under Tinted Glass
Use a Rotten Egg to make a patch of Dreadful Dirt, and build a room over it out of Tinted Glass so it stays dark but you can still see what’s going on. Keep the room small, as the Dreadful Dirt only needs a couple of blocks of space above it for the mobs to spawn.
Push the mobs out
Mob Fans and Entity Conveyors
Put a Mob Fan on one side of the room, powered with a Lever, pointing at a gap in the far wall. Add Width and Height upgrades until the whole room is covered, and run a short line of Entity Conveyors from the gap to wherever you’re going to kill the mobs.
Kill them in a Mob Masher
Powered, with Looting in it
End the conveyor in a Mob Masher with a redstone signal on it, and give it some Sharpness and Looting upgrades so the mobs die quickly and drop plenty. If you’re farming the player-only drops, this is the step that matters, as Iron Spikes won’t give you those.
Collect the drops and XP
Absorption Hopper into a Chest and a tank
Put an Absorption Hopper next to the Mob Masher, and set one side to push items into a Chest and another to push fluid into a Singularity Tank. From there you can bottle the XP, tap it, or turn it into Jelly Babies to run an Entity Spawner and grow the farm from there.
Tips for Mob Grinding Utils
Build the XP side first, even if it’s just Iron Spikes, an Absorption Hopper and a tank. Almost every advanced recipe in the mod uses a Fluid XP Bucket, including the chicken feeds for both eggs, so you’ll get stuck quickly without a tank of XP to draw from.
Keep a Lever on every Mob Fan, Mob Masher and Entity Spawner, as they all need redstone and it’s much easier to turn a farm off to work on it. The Mob Masher will hit you just the same as a mob, so switching it off before you walk into the killing area saves a lot of deaths.
A Wither Skeleton farm in a Nether Fortress, with ten Beheading upgrades in the Mob Masher, is one of the best things you can build with this mod. Every kill drops a skull, and with Looting in there too you’ll end up with far more Coal and Bones than you’ll ever need.
Tanks keep their fluid when you break them, which makes them easy to move around, but it also means an old tank can still be full of lava from something else. Craft it on its own to empty it before you connect it to your Absorption Hopper, so the Fluid XP has somewhere to go.
Mob Grinding Utils FAQ
Craft GM Chicken Feed Cursed from four Fluid XP Buckets, a Spider Eye, Rotten Flesh, Seeds, Bones and Gunpowder, then right-click an adult Chicken with it. The Chicken floats up and pops, dropping a Rotten Egg that turns a 5×5 area of Grass Blocks or Dirt into Dreadful Dirt.
The Mob Masher needs a redstone signal to run, so check it has a Lever or a Block of Redstone next to it and that it’s switched on. It only hits mobs that are inside its own block, so make sure your Mob Fan or conveyor is actually pushing them into it and not just against the side.
No, the Entity Spawner doesn’t check the light level at all. It needs a redstone signal, a Spawn Egg in the top slot, XP Jelly Babies as fuel, and room in its area for the mob to stand, although Zombies and Skeletons will still burn if you spawn them in daylight.
No, mobs killed by Iron Spikes don’t count as player kills, so they won’t drop anything that needs a player to kill them and Looting won’t apply. They do still drop their XP though, and if you want the player-kill drops you’ll need the Mob Masher instead.
