Lizard

Dr. Curtis Connors, a brilliant reptile biologist who lost his right arm, developed a serum derived from lizard DNA in hopes of regenerating his missing limb — but the formula transformed him instead into the savage, cold-blooded Lizard, bringing him into conflict with Spider-Man in their very first encounter.

Few villains in Marvel's Silver Age rogues' gallery have proven as enduringly haunting as the Lizard, who slithered onto the scene in The Amazing Spider-Man #6 in 1963, conjured by the legendary duo of Stan Lee and Steve Ditko at the very height of their creative powers. Over more than six decades of publication — racking up 232 catalog appearances and nine key issues that collectors prize — this reptilian menace has remained one of Spider-Man's most iconic and emotionally resonant adversaries. The Lizard keeps genuinely elite company, sharing pages with the likes of Doctor Octopus, Captain America, Iron Man, and J. Jonah Jameson, and has even crossed into the cosmic chaos of Marvel Super-Heroes Secret Wars. If you're serious about Spider-Man's world, the Lizard isn't just a villain to know — he's one of the essential, irreplaceable figures that define it.