Frogman

Any frogman can operate efficiently in clean water, under optimum conditions, but the Undertow are especially trained to function and fight in the murky, polluted waters that clog busy industrial and military waterfronts. His wetsuit is made of a nontoxic, anti-corrosive material. His facemask is coated with silicone to repel oil slicks, and is organically conditioned against hostile biological agents and infections.

"Undertow will swim through ANYTHING! This guy makes leeches look friendly! It's almost impossible to defeat him in his own environment! If we have to take him on in his own backyard, we first have to get tetanus booster shots before we move out for action. The best defense against this slime-swimmer is to keep a safe distance and throw grenades from behind a well fortified enclosure."