A stack of 130 cows.
Mob Stacking Behavior(top)
Stacking Radius and Limits(top)Stacking occurs when a group of at least five mobs are within a 10 block radius in each horizontal direction as well as a 5 block radius above and below from a central mob. The server checks for mobs to add to stacks every five seconds.
When two stacks are within the stacking radius of each other, the stack with the higher number of mobs in the stack is prioritized over the stack with the lower number of mobs. The number of mobs in a stack has an upper limit of 500.
On the Main Network Servers, stacking only affects mobs in the Mining world that are hostile. This is different from the Skyblock Server, which has mobs stack regardless of their hostility.
Stacking and Mob Traits(top)Mob stacking considers several unique features of mobs before placing them into mob stacks. Villagers of differing professions/robe colors, sheep that are sheared or not, slimes and magma cubes of different sizes, whether or not the mob is a baby mob, and mob color (llamas, wolves, parrot, and sheep).
Performing several actions to mobs will split them from the stack. These include shearing mooshrooms and sheep, dyeing sheep or llamas, breeding animals, and naming animals with a Name Tag.
Skyblock and Mob Challenges(top)On the Skyblock Server, mob stacks will only act as one mob (and not the amount in the stack) when being used toward challenges that require the player to be within range of several of one type of mob. In order to accomplish these challenges, players will need to be within range of the mobs before they have stacked or will need to nickname them with Name Tags in order to separate them.
Killing Mobs in Mob Stacks(top)Each time a mob is killed by a player bow/melee attack or sweep attack, 1-5 mobs are killed in the stack. The experience points gained from killing one of the mobs is multiplied by the number of mobs that are ‘killed’ from the stack.
If a mob stack is killed by fall damage, all mobs in the stack are killed. Any other means of mobs being killed (e.g. explosion, lava and fire, etc.) will cause only one mob to be killed. Mobs that only drop items after being killed by a player will retain this behavior if killed by non-player means.