Ex-Marine and Navy vet Rob Riggle sets out to help Basketball legend Shaquille O'Neal overcome his fear of sharks before he takes his first deep dive.

The UFC Hall of Famer claimed victories over plenty of fighters, but she'll face off with perhaps her biggest opponent yet when she goes swimming—uncaged—with Mako sharks. Luckily she'll have expert Navy diver and shark attack survivor Paul De Gelder on hand to coach her through the match.

Aaron Rodgers, Lindsey Vonn and Rob Gronkowski team up with scientists to learn about wildlife tags, which help researchers figure out where sharks feed, mate and birth their pups - crucial information that will help conserve the species.