The Lizard
You'rrre weeeeeak, jusssst like the ressst of humankind! They do not deserve to exissst in this world... in my world! Preparrre to join them. Prepare to diiiiie! 
- The Lizard
Dr. Curtis Connors (a.k.a. the Lizard) is a biologist who lost his arm in an accident and devoted himself into making a serum that could regrow missing limbs based on reptilian DNA, but secretly to regrow his own arm. This transforms him into a giant, humanoid lizard.
History
Early Life
Curt was born to a single mother in Florida. As a child, he developed as a gifted educator who spent his time studying science, primarily in animal science. One night, while his mother was close to coming home, she was attacked by a man she knew in high school and was savagely beaten by him for never loving him. Curt went into action and tried to save his mother, but had his right arm broken by the man and was beaten unconciously. At the hospital, he was told that his arm was almost damaged to the point that it could've been amputated, but the doctors were successful in fixing it. The experience traumatized him entirely and had to go to therapy with his mother to ease on the past events.
Oscorp
After getting a dectorate in animal science at college, he began working at Oscorp as an expert biologist. During this time, Curt loses his arm in a lab explosion and is forced to lose his job for his own safety, but learns how to work with his left arm easily. Before his resignation, he developed a way to cure human amputation through animal tissue, primarily with reptiles.
The Lizard
Dr. Connors gets a job as lead scientist at the Empire State University labs along with his wife, Martha Connors. Their son, Billy, usually hangs about the lab with them. He also gets a prosthetic arm from the director to help him with his studies. He hires Eddie Brock as his lab assistant. He is then greeted by interns Peter Parker and Gwen Stacy. Believing he lost half of himself because of losing his arm, he began a project on creating a regenerative serum made of lizard DNA. He injects himself with it frequently to help re-grow his arm. In a fight between Spider-Man and Electro, one of the vials is hit by Electro's electricity, amplifying the DNA within the serum. As a result of injecting the altered Lizard serum, Connors' arm re-grows as expected. However, Connors is later fully transformed into a human-like lizard. As the Lizard, he can't talk, yet he acts purely on animal instincts. He is extremely aggressive, shown attacking with little or no provocation, and even coming close to biting Billy. An antidote called a gene cleanser, developed by his wife, manages to restore back to his normal self.
When an alien symbiote was found and was sent to the ESU labs to be studied, the pair was ecstatic about the discovery and was given new hope to their lives and career. But after the robbery in which it gets attached to Spider-Man, they are distraught over the loss.
Evolution
The science department has Dr. Miles Warren as a new member as Norman Osborn funds the research. Dr. Warren has been conducting mutagenic experiments on human test subjects; he threatens to inform the school board only for Dr. Warren to blackmail him with his own lizard experiments. Later after all their trouble's and losses Curt and Martha decide to leave with Billy for the Florida Everglades to escape Warren's blackmail.
However, Dr. Connors is abducted by his old friend, Otto Octavius, who is now Doctor Octopus, before he and his family could leave for Florida. Upon learning his friend's lizard experiments and his own transformation into the Lizard, an insane Octavius decides to genetically enhance the lizard serum in Connors' DNA to try and kill Spider-Man. The experiment was too perfect, as it gave the Lizard a new feathery and muscular appearance, the ability to control other reptiles, the regaining of Connors' intelligence, and a new personality.
Octavius let the Lizard go on a rampage and gain Spider-Man's attention. Spider-Man believed that Connors made a new lizard formula to get revenge on Warren for blackmailing and leaving behind his career. He uses all the genetic cleansers at the ESU labs to try and cure him, but it proves not to be enough to stop him. He then contacts S.H.I.E.L.D. to try and stop the Lizard.
After he escapes S.H.I.E.L.D. custody, the Lizard, haunted of being threatened as a kid, tries to find Warren and get revenge for threatening and blackmailing him. He finds him and nearly kills him, and the rampage leaves the destruction of nearly all of the ESU labs. The Lizard has a fatally wounded Warren tied up in an underground lab, intending to torture him to make him feel the pain that he and his family had for being blackmailed. An arrogant Warren defends himself by saying that he brought it all upon himself and that he was trying to do what Connors never had the will to do by using mutagenic research to improve mankind. The Lizard then goes on torturing him until Spider-Man finds them, only for the Lizard to escape.
The Badoon
Trivia
- The Lizard in this universe is more similar to the Hulk. His transformation is based on Connors' emotional state.
- The Lizard also represents the "dark side" of Connors.