Ducks

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

Ducks can usually only spawn in the middle third of the above-ground world, and only in small to large pools of water. They can also spawn in areas nearby a house. Ducks rarely, but do say "quack" like a human.