Tiger Shark is an enemy of Namor the Sub-Mariner. He was once known as the Olympian swimmer Todd Arliss who damaged his spinal cord when he rescued a drowning man. He was then cured when a scientist experimented on him by blending the DNA of a tiger shark with Namor.
Todd changed physically and mentally and became a super villain. Some of his powers include: superhuman strength, superhuman speed (land and water) and heightened senses.