Francis Ngannou
Ngannou is one of the most frightening MMA fighters on the planet. But the Cameroonian knockout artist is involved in one of the strangest long-term dramas on this list. He won the UFC Championship and requested a title fight against Jon Jones. It made sense because Jones is a massive star and wanted to move up for a super fight.

But the UFC refused to pay Ngannou what he wanted and finally, negotiations broke down. In the end, Ngannou quit the promotion at the end of his contract and vacated the title. It was bizarre because there wasn’t an obvious fight for him outside of the organization. But Ngannou believed he could make more money from boxing (via Bloody Elbow).