There's a competition going on. A championship fight where the fighters are anything but normal. They are grown for the sport and their only goal is to take the competition out. They are the Fetus Fighters.
There are various groups around the globe that alter a fetus into a fighting machine. They do this with magic or science, and sometimes with both. They meet in various locations ranging from abandoned high school auditoriums to the basements of seedy bars in third world nations. The fighters go at each other one at a time and a fight lasts until the other cannot continue, usually this is death for the fighter. Prizes can be anything from money to more flesh to experiment on, but the real prize is just the fight itself. It's all about the creator’s ego.
It's a card game.
You have two decks. One is your Research Deck, from which you alter your various fetus into honed killing machines. The other is your Fight Deck, which you use during the fights for special moves and abilities. Each group has specific abilities unique to them and cards only they can use, or must use.
You play until somebody wins three fights. Simple as that. The goal is to keep it fast paced. Each player takes their turns at the same time so nobody has the edge of going first.
It's also not going to be for the squeamish or easily offended. But that's the way I like all my games nowadays.