Bunny

The Bunny is a background character that cannot harm players. Bunnies have only 5 health, and can be damaged by other mobs including the player, which almost always results in their instant death.

Bunnies can usually only spawn in the middle third of the above-ground world, and only on ordinary Grass. However, they can also spawn in areas nearby a house, including the Underworld.

During a Blood Moon, or when hit with Vile Powder, Bunnies will turn into Corrupt Bunnies, which have much more health and are aggressive.

During the Halloween event you can see bunnies wearing a Green Slime costume. There are also slimes that spawn wearing a bunny mask and tail.

Trivia

 * The Bunny can be seen on many of Terraria's logos.
 * In the Halloween update bunnies may wear a Slime costume.
 * In the 1.2.2 Christmas update bunnies may wear a Santa costume.

Tips

 * It's easier to farm for Bunny Banner if you have a Bunny Statue. Summoned monsters don't drop coins when they die, but they will still drop items.

History
Lapin Bunny Bunny Кролик