Fishface is a recurring boss character in video games. He is also playable in both his Xever and Fishface incarnations in Teenage Mutant Ninja Turtles Legends.
TMNT Legends Bio
Xever
There are times when only a low-level thug can get a job done. As long as Shredder pays, the slim Xever does what he is told. He is angry, tough, and cruel, and his sole focus is the pursuit of money.
Fishface
A Brazilian thief skilled in the martial art of capoeira, Xever mutates into a poisonous fish with razor sharp teeth. Baxter Stockman uses Kraang technology to build him mechanical legs. Once again, he is deadly on land.