9. CM Punk
The UFC had teased a CM Punk MMA debut for almost two years upon signing the former WWE superstar back in 2014.
Punk had unceremoniously left the leading pro-wrestling promotion and had hooked up with Duke Rufus’ gym in Milwaukee in preparation for a debut in mixed martial arts, but was fast-tracked once the UFC offered him a contract.
The WWE wrestler ultimately made his UFC and MMA debut against Mickey Gall at UFC 200, and the skill disparity was almost immediately on display.
Punk entered the bout at the already advanced age of 38 for a 0-0 mixed martial artist. Unsurprisingly, Gall toyed with the former pro-wrestler, who unlike fellow WWE to UFC defector Brock Lesnar, did not have the natural size or athleticism to carry him over into the world of real fighting.
Lesnar was a heavyweight who had to cut weight to make the 265-pound limit, and also had a collegiate and high school wrestling career to fall back on when it came to fighting in the UFC.
Conversely, Punk’s much smaller frame made him more suitable for the welterweight division, which has been one of the deepest and most dangerous weight classes in UFC history.
While Punk was indeed thrashed in his UFC and MMA debut, he vowed to continue training and fighting, but there has been no news of another fight since his loss to Gall.