Mother Slime

The largest of ordinary slimes, the Mother Slime starts spawning when you reach the Cavern Layer. Takes up 2x3 blocks of space (as opposed to the player: 3x2). Spawns 2-3 Baby Slimes when killed, but this can be avoided by killing the Mother Slime with a gun.

Like all other slimes, they drop coins and sometimes Gel when killed. Mother Slimes are found in Glowing Mushroom fields in large groups, along with other Black Slimes and occasionally some other mobs.

Similarly to the Black Slime, the color of this slime (which blends slightly with the background of the Cavern Layer) makes it 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.