The Lesnar Debacle
Brock Lesnar is one of the few people who successfully forged UFC and WWE careers. The former heavyweight champion stunned fans when he rejoined the former promotion for a headline fight against Mark Hunt at UFC 200. This went down after they controversially withdrew Conor McGregor from the high-profile card.
Lesnar won the match after he used his wrestling to full effect. Later, he failed a drug test after he tested positive for multiple steroids. Hunt sued the UFC because they put him in a dangerous situation against an obvious cheater. The promotion had no moral compass and poured millions into their defense (via Sportskeeda).