Fish

Fish is the host of Battle for Fish. It is not alive or sentient in any way, but the contestants think it is.

Appearance
Fish is simply a poorly drawn blue fish with crossed-out eyes. Its color changes slightly in every shot it appears in.

Personality
Fish cannot have a personality, because it is not alive.

Abilities
Despite not being alive, Fish displays an ability to move freely, which is demonstrated multiple times throughout the series. It is also capable of completely erasing objects from physical existence (which is used to eliminate players).