8. Jon Jones
Jones remains the youngest UFC champion ever. But perhaps the fame went to his head because he continues to go off the rails. He constantly creates problems for himself and the UFC suspended him multiple times. There were multiple drug test failures but the worst incident occurred in 2014.
That’s when he crashed his vehicle into a pregnant woman before fleeing the scene. It was a cowardly act and he received global condemnation. It also left the UFC with no choice but to act and they stripped him of his title. He also faced legal consequences because of his criminal actions (via N.Y. Post).