Name Auto-Spawner
Source Mod MineFactory Reloaded
ID Name
Type Block
Stackable Yes (64)
Blast Resistance 7.5
Hardness 1.5
Energy 32,000 RF
Solid Yes
Transparent No
Affected by Gravity No
Emits Light No
Flammable No
Required Tool Any tool will work, but a pickaxe is the most efficient.

The Auto-Spawner is a machine from MineFactory Reloaded which can spawn creatures when supplied with power, Essence, and a Safari Net storing a captured mob. Like any other powered MineFactory Reloaded block, it may take either IndustrialCraft2's EU power (at any voltage), BuildCraft's MJ, Universal Electricity power or COFHs' Redstone Flux.

Its single slot is used to store the Safari Net. Mobs stored in a Safari Net (Single Use) will not work in the Auto-Spawner. While the block itself is not especially expensive nor difficult to produce, it does compensate for this by requiring a large amount of energy per spawn. Additionally, it requires Essence to run. 150 mB of Essence are required per spawn (500 mb for exact copy), while the Grinder only generates 100 mB per mob, meaning that, when using a Grinder, essence from three mobs is required to spawn two mobs with the Auto-Spawner.

In newer versions however, the auto-spawner as well as the grinder received some balance updates, as a player could easily exploit the spawner with sewers and fake players / Melee Turtle combo, giving more essence back than what was required to spawn the mob in the auto-spawner. The grinder now gives the same essence as a melee turtle, or fake-player kill. In the newer version, the amount of essence to spawn a mob varies with the work units required by the machine, which in turn varies based on the mob.

One work unit equals 10 mB of mob essence and 600 RF as of 2.8.0RC3-591 there is extra energy cost of spawning an entity (+600RF), this might be a bug

  • delay between spawns (in perfect conditions, in seconds) is mob work units / 20 = delay in seconds
  • total essence cost = work units * 10 mB of essence
  • total energy cost = work units * 600 RF + 600 RF
  • delay between spawns = work units / 20

so to spawn two cows it would take 26 * 600 + 600 + 26 * 600 + 600 = 32400 RF 26 * 10mB + 26 * 10mB = 520 mB of essence Here are a few tested mobs with the newer version of MFR (average value after 100 entities)

Mob grinder (mB*) average (mB*) auto-spawner (mb and rf) normal (wu*) exact copy (wu*)
Creeper 332 - 530mb+32400rf 53 266
Skeleton 400-532 486.6 860mb+69600rf 86 433
Spider 332 - 530mb+32400rf 53 266
Zombie 332 - 530mb+32400rf 53 266
Enderman 332 - 530mb+32400rf 53 266
Cow 66-200 133.3 260mb+16200rf 26 133
Villager - - 260mb+16200rf 26 133
Blaze 666 - 930mb+75200rf 93 466
Blizz 666 - 930mb+75200rf 93 466

work units*

Mili-buckets of mob essence*

For the Auto-Spawner to function, enough room has to be provided for the mob type in the Safari Net to spawn. A 9x9x5 room (with the spawner in the center on the floor) is large enough to hold most mob types, and will ensure that they do not escape.

The auto-spawner itself has an area of effect of 9 × 9 × 3 (1 block above the spawner, 1 below), meaning that you would need a 9 × 9 × 3 room to spawn say, bats without any escaping.


An Auto-Spawner being used with Conveyor Belts in a Skeleton mob farm.

It is possible to construct a fully automatic mob farm using the Auto-Spawner and other MineFactory Reloaded machines. Auto-Spawners can be used as a mob source and Conveyor Belts can transport the mobs to a Grinder, which will kill the mobs and collect their drops and essence. The essence can then either be used to supply more Auto-Spawners or an Auto-Enchanter.

Blacklisted Mobs[edit]


  • Due to Wither Skeletons and Skeletons sharing the same mob ID, the "Spawn Exact Copy" option in the Auto-Spawner GUI has to be enabled to spawn Wither Skeletons in the Overworld.
  • The heads of the Hydra from Twilight Forest may be spawned with an Auto-Spawner, but will be passive and unable to take damage. They may be removed again with a Safari Net.
  • Using it to spawn slimes larger than tiny ones, if not using Exact Copy, will likely allow a profit of Essence to be made with the Grinder, as the medium slimes will spawn smaller ones, all of which count as Grinder kills.
  • If trying to spawn a Ghast, you need a 6 by 6 spawnable area inside your Auto-Spawner chamber


Thermal Expansion[edit]

GUI Crafting Table.png
Plastic Sheets
Nether Wart
Plastic Sheets
Magma Cream
Machine Frame (Basic)
Magma Cream
Redstone Reception Coil


Auto-Spawner has no known uses in crafting.



If Melee Turtles, Autonomous Activators (with unbreakable weapons such as reinforced X on tinkers' construct broadswords) or other experience orb dropping machines are used to grind the mobs and these experience orbs are converted to mob essence by a Sewer, the Sewer generates 500 to 800 mB mob essence per mob. This means that, even if the Auto-Spawner is making exact copies, enough mob essence is generated to sustain the Auto-Spawner. This is fixed in newer versions.