The Amazing Spider-Man #003 (1963)
“Spider-Man Versus Doctor Octopus”
Writer: Stan Lee
Artist: Steve Ditko
The 1st appearance of Doctor Octopus, in which Doc Ock gets his mechanical arms fused to his body in an accident. Spider-Man is defeated by him in their first battle, but later comes back and knocks out Doc Ock, since other than his extra arms, he has no super strength or powers.