An Antarian Mankiller was a kind of animal considered to be one of the deadliest predators in United Federation of Planets space.
An extremist faction of the Vardaine managed to genetically engineer an even deadlier version of the Antarian mankiller. This animal was brought on board Espoir Station by Doctor Ies Bredell, and placed behind a force field in the special projects room - which held the tractor beam controls - which themselves were behind a forcefield. When the forcefield for the controls was released, the force field holding the mankiller was also released. When Captain James T. Kirk, Commander Spock, and Doctor Leonard McCoy entered the room the mankiller was standing next to the controls. Captain Kirk took out his phaser and vaporized the animal before it could attack them. (TOS video game: Judgment Rites)