Andy Ruiz
Ruiz’s story is one of the most incredible ever. The Mexican boxer fought Anthony Joshua as a late replacement in 2019. Nobody expected the dumpy fighter to stand a chance against the UK’s chiseled Adonis. But he stunned the world when he knocked Joshua out in the seventh round.

This made Ruiz the first Mexican heavyweight champion ever. But fame went to Ruiz’s head and it cost him dearly. Joshua activated the rematch clause but Ruiz didn’t train properly. Joshua won a convincing decision in the rematch as Ruiz followed in Buster Douglas’s footsteps (via National World).