Bunny

The Bunny is an NPC added in the 1.0.4 patch. It can be seen on many of the Terraria logos. By itself, it is a friendly creature with 5 HP, which is damaged by monsters, and is incapable of dealing damage. However, if you throw Vile Powder on it, or there is a Blood Moon, it turns into a Corrupt Bunny.

Bunnies do not move at night time, instead opting to stand in one place until sunrise.

Also they are cute, so much so, that when a slime kills a bunny all you want to do(if you're a nice person) is to entirely obliterate the slime, and its ashes.