Todd Arliss was swimmer who took part in the Olympic Games. He damaged his spinal cord when he rescued a drowning man. Desperate to regain his swimming ability, Arliss willingly participated in an experiment by the scientist Dr. Lemuel Dorcas.^[2] Dr. Dorcas blended Arliss' DNA with that of Namor the Sub-Mariner and a tiger shark. Although successful, the process changed Arliss both physically and mentally: he now had razor-sharp teeth and gills and had become savage and predatory. Becoming a super-villain and calling himself Tiger Shark, he found and threatened Lady Dorma and was then crowned Lord of Atlantis.^[2] The Sub-Mariner, however, soon deposed Tiger Shark and the two became implacable foes.^[3] Namor and Dorma travelled to the surface to tell Tiger Shark's sister Diane Newell that he was still alive.^[4]

Namor sought Lord Seth's help to find the Herb of Healing to help restore Tiger Shark to human form, but Namor failed his quest.^[5] Tiger Shark was next seen near the Sargasso Sea. Namor confronted Tiger Shark who had allied himself with a group of Immortals bent on ruling the world. However, when the Immortals left the mists of the Sargasso Sea, they began to age instantly and die. Tiger Shark attempted to unleash a deadly virus, but Namor and the sacrifice of Dr. Newell ensure that it caused no harm. Tiger Shark escaped, but Namor vowed to kill him when they next meet.^[6]

Llyra and Tiger Shark worked together and unleash the sea monster Krago. With the help of the Human Torch, Namor drove back Krago.^[7] Namor faced off against Llyra and Tiger Shark, but their battle was interrupted as the Human Torch showed up. An enraged Namor fought against the Human Torch not knowing that he wanted to help. Namor defeated the Human Torch and then learned that his father, Leonard Mackenzie, had been kidnapped by Llyra and Tiger Shark.^[8] Namor desperately attacked Tiger Shark while Llyra kept an eye on Leonard. After Llyra tired of their battle and captured Namor, Stingray came to Namor's rescue. They confronted Llyra and Tiger Shark together, but Tiger Shark killed Namor's father. The villains fled while Namor mourned the loss of his father,^[9] and Tiger Shark hid in the Niagara Falls.

When the Hulk happened to crash in the Niagara Falls, Tiger Shark attacked him under the impression that the Hulk had been sent by Namor to get revenge. The two battled and the Tiger Shark overpowered him after their submersed. In need of air, the Hulk returned to dry land, and Tiger Shark followed him. This proved to be the villain's undoing, as the Hulk managed to easily defeat him in land. The Hulk slammed Tiger Shark into rocks before throwing his unconscious body into the waters below.^[10]

Tiger Shark later moved to New York City, but he was tracked down and attacked by Namor, who had teamed up with Spider-Man. Tiger Shark allied with Dr. Dorcas, who had been developing men-fish called Aquanoids to be his army of aquatic mutates. When Namor and Spider-Man arrived on Dorcas' ship, the two fought off both Tiger Shark and Dorcas' Aquanoids. Spider-Man and Namor were forced to abandon ship when devices within the vessel become unstable. Getting to safety, the two watched as Dorcas' ship explodes, seemingly killing Tiger Shark and Dorcas in the process.^[11]

Tiger Shark later reappeared to team-up with Attuma and Doctor Dorcas to capture Hydro-Base and take Namor prisoner there. Namor regained his freedom with the help of Doctor Doom, and attacked the conspirators, throwing Tiger Shark into one of Attuma's war machines. As Dorcas was able to fire a lethal blast from his hand weapon at Namor, the machine toppled on top of Dorcas and crushed him to death.^[12] After escaping from Hydrobase, Tiger Shark abducted Namor's cousin Namorita. His plan was foiled by Ms. Marvel.^[13]

Tiger Shark would later join two incarnations of the Masters of Evil.^[14] During the first instance, Tiger Shark aided Egghead in a plan to ruin Hank Pym, but ultimately failed.^[15] The second time, Tiger Shark was recruited by Baron Helmut Zemo and took part on the attack on the Avengers Mansion.^[16] The team was ultimately defeated.^[17] Arliss and fellow Masters of Evil member Whirlwind escaped to California, where both are captured by Avengers West Coast members Tigra and Hellcat.^[18] Shortly afterwards, Tiger Shark took part of a master plot by a cabal of supervillains to force superheroes confront villains they were not used to. Tiger Shark battled Wolverine.^[19]

After escaping prison, Arliss battled Stingray.^[20] Tiger Shark ceased hostilities to help rescue his sister, who had become trapped in a cave-in after being captured for study and then rescued by Namor.^[21] For a time Tiger Shark renounced crime, and renamed himself Arlys Tigershark, and married a woman from an undersea tribe of nomads.^[22][23]

Tiger Shark reverted back to his old ways when his pregnant wife and her tribe were slaughtered by savage undersea creatures called the Faceless Ones.^[24] He helped Namor battle Suma-Ket, the master of the Faceless Ones, who led an attack on Atlantis that failed when Suma-Ket was killed in battle.^[25]

Working with the aquatic Inhuman Triton and the Fantastic Four,^[26] Tiger Shark reluctantly helped Namor fend off an alien invasion.^[27] Shortly afterwards, Tiger Shark fought against Namor's nephew Llyron,^[28] and later joined a team called the Deep Six to battle the Avengers.^[29] The Deep Six tried to conquer Atlantis.^[30] The Deep Six initially succeeded, but they were defeated by the Silver Surfer.^[31]

Tiger Shark rejoined the Masters of Evil lead by a new Crimson Cowl, Justine Hammer. At this time he mutated into a more shark-like creature, complete with grey skin and a fin. The team battled the reformed villains the Thunderbolts.^{[32][33][34][35]}

Tiger Shark was imprisoned in the Big House, where inmates were shrunk using Pym Particles. Escaping with several other inmates at microscopic size by riding on the back of She-Hulk's hand, Tiger Shark and the other villains emerged and attacked when she visited a law firm. Tiger Shark was defeated when She-Hulk threw the villain Electro into the water Tiger Shark was standing in, short-circuiting Electro and causing Arliss' electrocution.^[36] Tiger Shark was imprisoned in the Raft, from where he escaped during a mass breakout.^[37] He was recaptured by the New Warriors along with fellow villain Armadillo.^[38]

After the Civil War, Tiger Shark was next involved in the theft of an artifact called the Horn of Gabriel, which he used to summon huge sea monsters and then directed them against the surface world. Arliss was defeated by Namor and the Mighty Avengers.^[39] Some time later, Tiger Shark was captured by Alexei Kravinoff as part of the hunter's plan to create a collection of animal-themed superhumans. Tiger Shark was one of his captives in a water tank.^[40]

When the criminal The Hood became a crime lord, he decided to take advantage of the split in the superhuman community caused by the Civil War to assemble an army of supervillains. Tiger Shark was a member of The Hood's Gang.^[41] Around this time, Tiger Shark attempted to extort money from Norman Osborn, the leader of the new Thunderbolts, but he was beaten into submission by Venom and forced to secretly work for Osborn.^[42]

During the the Skrulls' Secret Invasion of Earth, Ms. Marvel saved Tiger Shark from being killed by an alien Super-Skrull in the Raft.^[43] Some time later, Tiger Shark was drafted by the Gamesmaster to be a member of the Offenders (a team led by The Red Hulk) whose goal was to destroy the Defenders.^[44]

After the mercenary Deadpool provoked Osborn, Tiger Shark was sent to kill him. Tiger Shark was shot down into the water by Deadpool's sidekick, Bob.^[45] When Bob and Deadpool regrouped back in an apartment, Bob told Deadpool about how Osborn wanted him dead, and that Norman had also hired Bob to help Tiger Shark deal with him, and that Tiger Shark was coming for them.^[46] Deadpool pretended to use the bathroom so he could sneak up behind Tiger Shark with a gun, but he was knocked to the ground and was forced to choke strangle Tiger Shark with a curtain before being able to unload a burst of bullets into Tiger Shark's chest.^[47]

Tiger Shark joined a newer version of the Lethal Legion, led by the Grim Reaper.^[48] Tiger Shark, Absorbing Man, Mr. Hyde and Grey Gargoyle attempted to steal an armor truck filled with money at the New York Harbor. They were stopped by Hawkeye and the Avengers.^[49]

During the War of the Serpent, Liz Allan and Normie Osborn encountered two men, one of whom was wounded by Tiger Shark during a bank robbery.^[50][51] Tiger Shark later joined Nerkodd: Breaker of Oceans, Tyrak, and Aradnea in conquering New Atlantis.^[52][53] As Namor and his army fought off Nerkodd's forces and the Undying Ones, Loa (Alani Ryan) was attacked by what appeared to be a two-headed Tiger Shark.^[54]

After joining Misty Knight's Crew for a short while,^[55] Tiger Shark became a member of the Shadow Council's incarnation of the Masters of Evil.^[56] Some time later, Tiger Shark was captured by S.H.I.E.L.D. and imprisoned at Pleasant Hill, a clandestine superprison that used a sentient Cosmic Cube to transform their inmates into model citizens of a small town.^[57] Most villains escaped from Pleasant Hill following a breakout.^[58]

After Namor changed his policy on the relationship between the ocean and the surface, he prepared to declare his territory off-limits to all but its native inhabitants. Tiger Shark had attacked a cruise ship in an attempt to impose a toll for traversing his waters when Stingray engaged him. Namor approached the two combatants to present them with the ultimatum to either join them or die. Stingray tried to reason with Namor, but was beaten up and left for dead at the mercy of Namor's War Shark. Left with no other choice, Tiger Shark accepted to join Namor's side, and became a member of his Defenders of the Deep, Namor's own super-team assembled to impose his will on the surface world's presence in the oceans.^[59]

• Atlantean/Human/Tiger Shark Hybrid Physiology: Doctor Dorcas' blending of Arliss' DNA with that of a tiger shark and the Sub-Mariner grants him a unique, amphibious physiology granting him a number of superhuman attributes.
  • Superhuman Strength: Tiger Shark possesses great physical strength that varies greatly depending upon the amount of time he spends out of water. His strength is sufficient enough to engage Namor in direct physical combat. While wet, Tiger Shark possesses sufficient superhuman strength to lift up to 75 tons. When dry, however, his strength is significantly less and can lift about 50 tons. The least amount of weight Tiger Shark has been able to lift is about 40 tons, but only after being dry for an extended period of time.^[60]
  • Superhuman Speed: While on land, and wet, Tiger Shark is capable of running and moving at speeds greater than even the finest human athlete.^[60]
  • Superhuman Swimming Speed: While in water, Tiger Shark is capable of swimming much faster than the finest Olympic swimmer. He can reach a top speed of 60 miles per hour.^[60]
  • Superhuman Stamina: While wet, Tiger Shark's musculature produces considerably less fatigue toxins during physical activity. His musculature also generates far less fatigue toxins than the vast majority of Atlanteans, who all possess some level of superhuman stamina. He can exert himself at peak capacity for about 24 hours before fatigue begins to impair him.
  • Superhuman Durability: While wet, Tiger Shark's body is considerably harder and more resistant than the body of an ordinary human, or most Atlanteans for that matter. He is capable of withstanding the extreme temperature and pressures of the ocean floor, powerful impact forces, high caliber bullets, and falls from great heights without sustaining injury.
  • Superhuman Agility: While wet, Tiger Shark's agility, balance, and bodily coordination are enhanced to levels that are beyond the natural physical limits of even the finest human athlete.^[60]
  • Superhuman Reflexes: While wet, his reaction time is enhanced to a level that is beyond the natural physical limits of even the finest human athlete.^[60]
  • Regenerative Healing Factor: Despite his superhuman durability, it is possible to injure Tiger Shark. However, like Atlanteans, he is capable of rapidly healing minor and moderate injuries faster than ordinary human beings, provided he is wet.
  • Aquatic Physiology: Tiger Shark's body is specially adapted for aquatic environments. His body is capable of withstanding cold temperatures and pressures that are found on the bottom of the ocean floor. He is also capable of breathing, speaking, seeing, and hearing underwater with perfect levels of clarity.^[60]

• Olympic Swimmer: Before gaining his superhuman powers, Todd Arliss was a record-breaking Olympic swimmer. His sheer strength and physical toughness make him a formidable combatant.

• Tiger Shark's vitality is dependent upon regular exposure to water. The longer he is out of the water, most of his superhuman abilities rapidly dwindle. If he is removed from water long enough, it could prove fatal.^[60]

• Tiger Shark's costume is specially designed and contains a built in water system that constantly keeps his body wet. This keeps him in peak physical condition if he's out of the water.

• Adamantium teeth When he appeared as a member of the Offenders, he had Adamantium bonded to his teeth. It is unknown how or when this happened.

• Tiger Shark has been identified as one of the 142 registered superheroes who appear on the cover of the comic book Avengers: The Initiative #1.
• Tiger Shark's early appearances are reprinted in various comics.^[61][62]
• As a prominent villain Tiger Shark has appeared in various flashbacks.^{[63][64][65][66][67][68][69][70][71][72]}