Rabbit is a game type in Tribes 2 and Tribes: Ascend.
In a Rabbit game there is one flag and all players try to get it. Once a player has the flag they become the "Rabbit" and all other players try to kill them and take the flag. Players earn points the longer they hold the flag, for killing the rabbit, or for killing other players while they are the rabbit. Even when you are the rabbit you can still attack the other players.