"The first player to score a frag becomes the Mutant. Everyone else hunts the Mutant, as by killing the mutant, a player becomes the mutant, with superhuman powers. The player with the lowest score is the Bottom Feeder. He can also kill other players."
"A Mutant game starts out as a free-for-all deathmatch. However, as soon as one player makes a kill, he becomes the Mutant. Everyone else stops fighting (you can’t hurt each other anymore), and guns for the Mutant instead.
Mutants get all (non-super) weapons, lots of ammo, and have invisibility, agility and berserk. However, the Mutant’s health slowly runs down and can only be replenished by killing other players. Also, the Mutant’s position appears on everyone else’s HUD. If a player kills the Mutant, they become the new Mutant.
As an optional twist, the player with the lowest score is the Bottom Feeder — he can also go kill other players to score points. As soon as the Bottom Feeder’s score isn’t the lowest, a new player becomes the Bottom Feeder."
The gametype is available in UT2003 only by installing the Epic Bonus Pack.
"There is one gametype that we're testing now called "Mutant" in which one player is the bad guy and he is invisible and he has regenerating health. Kill him and you become the mutant; the player who lasts the longest wins. Bear in mind that everyone's radar is tracking your location when you're the mutant, of course. It's quite a bit of fun. Any other mutators/gametypes remain to be seen."