In video games, team killing or TKing refers to the act of purposely killing another player on the same team as their own. It happens mainly in First-person shooters (FPSs) and any game where players have the ability to kill either players on a different team, or Artificial intelligence. Team-kill is often abbreviated as TK, the person being "TKer". Team-killing may simply be an episode of friendly fire, due to disorientation or being a new player. However, team-killing just as often employed by griefers (who are not actually playing the game) or by disgruntled players, perhaps in retaliation for being a victim themselves. Team killing is also employed by gamers who have also became bored of the game. It is also used by gamers to force a reaction from their teammates.