Select any character, then change his or her name to the following:

Code      Result 
Sthelens  Volcano course 
Ufo       Play as an alien 
Tigerrrr  Play as a tiger
Liltiger  Play as Tiger in 70s costume 
Prodigy   Play as Tiger in 80s costume
Retro     Play as Inga in flower power costume 
Ice       Play as Chip with goatee
Safari    Play as Traci in leopard costume
Rapper    Play as Mimi
Cybertw   Play as Twfan
Willi     Play as Eagamer
Brat      Play as Bobby
Instyle   Play as Cindy
Delvis    Play as Delvis    
  
   

Thanks to Revolution readers Angel Ramirez and Mike Clementz!