2025 Shark Week Special. Hundreds of miles off the coast of Columbia, Phil and Heather join a scientific team trying to locate and tag El Monstruo, a huge shark seen in the waters off Malpelo Island, home to unique shark populations.

Phil and Heather investigate disturbing reports of aggressive mutant sharks in Micronesia's Marshall Islands. Joined by a team of scientists, they dive in dangerous waters to explore whether the region's terrifying atomic past is to blame.