Dr. Curt Connors was a medic in St. Martin Hospital who helped Peter Parker when he injured his shoulder.
At an unknown point in both Curt and Peter's life, Connors created a serum in hopes of regenerating his lost right arm and became a humanoid reptile that would become one of Spider-Man's earliest foes, the Lizard, until Peter created a cure using Curt's blood. The cure only worked temporarily, however, and it appears that Connors was still roaming around somewhere in New York City. While he does not appear in Marvel's Spider-Man, Peter kept the vial of blood as a memento.
Connors is seen in his human form working for Norman Osborn, examining and studying his son and his disease. Norman said to release him from his container, insisting angrily against Connors' advice, leading Connors to do so.