Tiger Shark is a supervillain from Marvel comics and an enemy of Namor the Sub-Mariner, as well as the Avengers. He began as Todd Arliss, an Olympic swimmer who damaged his spinal cord, and could no longer swim. He was then subjected to an experiment to heal him, in which the DNA of Namor the Sub-Mariner and a tiger shark were mixed and injected into his own. He was healed, but it also transformed him into a shark-humanoid creature with sharp teeth, fins, and gills, as well as a savage and bloodthirsty nature.
Tiger Shark became a lifelong enemy of Namor, and has also battled the Hulk and a few other Marvel heroes. He also joined Egghead's Masters of Evil and fought the Avengers. At one point he forsook his villainous life and married a woman from an undersea tribe, but returned to crime after her and her tribe were slaughtered.