Slimeballs are items dropped by green slimes when killed. Green slimes spawn in any swamp biome at night time, or in certain chunks below Y-level 40 at any light level. There are three sizes of Slime-- Small, Medium and Large. Large Slimes will divide themselves into smaller versions when killed, increasing the potential amount of slimeballs they can drop. Slime balls can alternatively be created with milk and lime dye in a Factorization Crystalizer. Slimeballs are also dropped by Maze Slimes, found in Mazes of the Twilight Forest, oftentimes dropping 32 or more per large slime.