Black Slime

The Black Slime only spawns in the cavern layer, often accompanied by Mother Slimes. Like all slimes, they drop some Gel and Coins. Black Slime attacks have a chance to cause Darkness, which decreases the distance light travels, making light sources less effective and the general area more dark.

Due to its color, which blends slightly with the background of the Cavern Layer, this type of slime is hard to detect if the player isn't paying attention, or if the slime spawns in and moves out of a dark area. As such, it can often catch players off-guard.