Maybe Tony Ayala Jr. The guy had some serious mental problems. Guys like Tyson and Golota at least MADE it and made money, Tony had all the talent in the world but blew it with his insanity.

-He spit on an opponent after knocking him down.
-Admitted to shooting up heroin before 3 different fights.
-Several cases of rape and brutalizing women outside of the ring, including one when he was 19 that sent him to jail for 16 years.
-Gets out of jail, braeks into a girls home and gets shot in the shoulder.
-Gets out of jail, is charged with having sex with a 13 year old, but the charges are dropped.
-Sentanced to another 10 years in 2004 for violating parole.