Billy was born in Florida to Curt and Martha Connors, the former of whom is a biologist. The family moved to New York City so that Curt could continue his research in limb regrowth. The result was that Curt transformed into the Lizard and chased Billy in an attempt to eat him. Luckily, Billy was rescued by Spider-Man who turned his father back to normal with the antidote to the Lizard Formula. During a major story arc, Martha and Billy were kidnapped by the Maggia branch led by Silvermane who wanted Curt to decipher an ancient tablet. Once again, Curt transformed into the Lizard and it took the combined effort Spider-Man and the Human Torch save Martha and Billy who were happily reunited with a cured Curt. At one point, Billy was kidnapped by the villain Stegron who demanded that Curt aid him in reviving a dinosaur army. Spider-Man and Lizard fought Stegron and saved Billy from a terrible fate. Curt eventually chose to leave his family greatly saddening Billy and Martha. However, Curt came back and turned Billy into another lizard creature dubbed Lizard Jr., but the two were captured and turned back to normal by Spider-Man. Sometime later, Curt mentions that Martha and Billy contracted cancer. Martha died while Billy survived, but was forced to live with his aunt. During The Gauntlet and Grim Hunt storyline, Lizard finally devoured Billy resulting in Lizard becoming a creature called the Shed. In a lead-up to the storyline, Billy was revived by Miles Warren, along with Martha, so that Curt could have a reason to work for him. When New U Technologies suddenly breaks out in a melee, Billy and Martha are taken away by Curt who claims that he can cure them of the Carrion Virus. Billy and Martha are injected with the lizard formula, turning Billy back into Lizard Jr., saving their lives, but now making them lizard-human hybrids. While Billy and his family have begun to live peacefully in the sewers, getting occasional friendly visits from Peter Parker and Mary Jane Watson, he has started to openly talk of his longing to visit the outside world and attend a regular school; adding that kids with unusual appearances and abilities have begun going as well. Despite this, his father angrily rebuffs his pleas and he in turn has started to rebel. He is later captured and used as a hostage by Kraven the Hunter as part of Kraven's efforts to test his cloned 'offspring' and provoke Spider-Man into becoming the 'hunter' Kraven feels his enemy should be. When trapped in a cage with Connors, Spider-Man learns that Connors took Billy to Doctor Strange after his resurrection, with Strange confirming that, for reasons he cannot understand, Billy is not 'just' a clone of the original Billy Connors, but is actually Billy's soul reborn in his cloned body, driving Connors to be willing to take any measures necessary to protect his son.
In an issue of What If? that asks "What If Spider-Man Killed the Lizard?, Billy learns that his father was the Lizard and swears revenge on Spider-Man for murdering him. Billy intentionally amputates his arm to be like his father and is later visited by Calypso who gives him an elixir that transforms him into another lizard monster.
In other media
Television
Billy makes his animated debut in the Spider-Man, voiced by Billie Mae Richards. Here, he is named Billy Conner.
Billy Connors appears in Spider-Man: The Animated Series voiced by Toby Scott Ganger.
Billy Connors appears in The Spectacular Spider-Man voiced by Max Burkholder. He is a very happy kid that hangs out at the lab with his scientist parents. Billy is the first to realize that his father is transforming into a lizard and fears that his father would forget him. When Connors finally transforms into the Lizard, Billy tries to appeal to his human side which is enough for Spider-Man to feed Curt the formula to change him back. In the episode "Final Curtain", Billy and his family are forced to move to Florida after Miles Warren blackmails Curt by threatening to reveal his Lizard experiments to the board of education if Curt revealed Miles' involvement with the supervillain community.
Film
Billy Connors was supposed to appear in The Amazing Spider-Man played by Miles Elliot, but his scene ended up getting cut. Curt visits Billy at the bus stop to inform him that he is "going away for a while" and tells him that he and Martha were wrong about "not striking back", causing some confusion for Billy.
