A noted geneticist funded by Stark International who lost his right arm under unrevealed circumstances, Curt Conners dedicated himself to finding a means of restoring lost limbs, studying the regenerative capabilities of reptiles; however, after five years without major breakthroughs, his sponsors were on the verge of cutting his funding. Drowning his disappointment with alcohol, the drunken Conners injected himself with an experimental serum in a desperate attempt to achieve results. The serum regenerated his right arm, but it also transformed Connors into an inhuman reptilian creature. Seeking refuge in the sewers, he became an urban legend, dubbed "The Lizard" by the press. A sympathetic Spider-Man sought out Conners who attacked the young hero until the Man-Thing happened upon the scene and restored Conners to human form. Conners’ restored right arm soon withered and died; however, his DNA remained irreparably damaged, with dormant potential for further transformation, and he cut himself off from his wife and son out of fear for their safety. 
Connors turned to research on the experimental biological "suit" designed by Richard Parker, but his work was undercut when Spider-Man, secretly Richard’s son Peter, tested the Suit’s capabilities, and one of Conners’s students, Eddie Brock, absconded with a second sample, then battled Spider-Man while wearing it. When Spider-Man returned to the lab. Connors, who had watched reports of the young hero’s activities and deduced his identity, was waiting him. Although Conners only vaguely recalled their earlier meeting, he felt that he owed the youth a debt and offered to assist him in any way possible.
Weeks later, haunted by dreams of his reptilian persona, regretting his impulsive separation from his family, and once more facing funding cuts, Conners sought solace in late-night lab work, only to be interrupted by the arrival of Spider-man, newly injured by the Gladiator. After treating his friend’s wounds, Conners studied a sample of Peter’s blood and was galvanized by its genetic potential. With Peter’s permission, Conners subjected the sample to several experiments over the next two months, earning additional research money and ultimately creating “Little Ben”, a rejuvenating organism created by splicing the altered DNA of both Connors and Spider-Man with the final sample of Richard Parker’s work; however, the creature escaped the laboratory and killed several people, including Gwen Stacy. After Spider-Man seemingly destroyed it, Conners, devastated at having once more wreaked havoc via reckless experimentation, confessed his involvement in the deaths and surrendered himself to the police.
Conners was later pardoned and recruited by S.H.I.E.L.D. and worked alongside with Tony Stark on interviewing with Gwen Stacy (the Stacy Experiment, which was in fact the new Carnage), when the Triskellion was blown apart by Norman Osborn, upon his escape.
While transformed into The Lizard, Connors possesses a variety of superhuman attributes:
Superhuman Strength: Connors himself has the normal physical strength of a human male of his age, height, and build that engages in little regular exercise. While transformed, he possesses sufficient superhuman strength to lift about 12 tons. His physical strength has extended into the muscles of his legs allowing him to leap about 18 feet into the air.
Superhuman Speed: While transformed, Connors can run and move at speeds greater than that of the finest human athlete and can reach a top speed of about 45 miles per hour.
Superhuman Stamina: While transformed, Connors' advanced musculature produces considerably less fatigue toxins during physical activity than the musculature of an ordinary human. He can physically exert himself at peak capacity for about 24 hours before fatigue begins to impair him.
Superhuman Durability: While transformed, Connors' scaly skin and superhumanly enhanced bodily tissues provide him much greater resistance to physical injury than an ordinary human. He can withstand great impact forces, falls from great heights, and small caliber bullets without sustaining injury.
Superhuman Agility: In his transformed state, Connors' agility, balance, and bodily coordination are enhanced to levels that are beyond the natural physical limits of even the finest human athlete.
Superhuman Reflexes: Connors' reflexes are similarly enhanced while transformed and are superior to those of the finest human athlete.
Regenerative Healing Factor: Despite The Lizard's physical durability, he can sustain physical injury. However, if injured, his body is able to rapidly regenerate damaged or destroyed tissue with much greater speed and efficiency than an ordinary human. While transformed, Connors' healing powers are developed to the point where he can fully regenerate missing limbs, just like many known reptile species.
Tail: While transformed, Connors has a long, reptilian-like tail that he can use to help balance himself or as an offensive weapon. He is capable of whipping his tail at speeds of at least 70 miles per hour. Considering his strength and physical toughness, he can generate enough force to shatter concrete. Like some geckos, The Lizard can detach his tail and grow a new one.
Fangs & Claws: While transformed, Connors' fingers and toes are each tipped with razor-sharp claws that, combined with his natural strength, are able to cut most conventional materials, including flesh, bone, wood, stone, and some types of metals. His mouth is also filled with rows of razor-sharp teeth that he can use as offensive weapons in close combat situations.
Conners is a brilliant geneticist, albeit hindered by depression and alcoholism.
Curt Conners has three unspecified doctorates relating to bioengineering.