- Michael Morbius (First appearance as a vampire-like creature)
As Spider-Man swings through the city, thinking about how Doctor Mariah Crawford may have a cure for his mutation, he overhears a robbery and proceeds to catch the crooks as they get away in their vehicle. However, he suddenly experiences extreme pain as a result of his mutation, and the crooks prepare to shoot him as he is lying on the floor in pain, but the police arrive just in time to chase them away.
After getting away, Spider-Man visits Dr. Crawford, and tells her about the pain he is experiencing. However, she gives him good news, telling him that she is making progress searching for a cure and has developed a serum which may be able to return his blood cells back to normal, but it may inadvertently destroy him or remove his spider powers altogether. When Spider-Man insists on taking the serum immediately, Dr. Crawford tells him not to yet until she has finished it, causing him to start smashing up her lab, although she manages to persuade him to stop by mentioning that he is turning into the monster he fears to become. She allows him to take the serum, but warns that it may be a big mistake, and he leaves.
Peter takes the serum to his lab at E.S.U. and plans to test it on his blood from outside his body first, unaware that Michael Morbius is spying on him. Before leaving, Peter puts the serum inside his locker, and after he is gone Morbius opens his locker, wondering what he is up to and assuming it is to do with the neogenics competition for a place as Dr. Connors's assistant at the university. Morbius analyses Peter's mutated blood sample and the serum, and concludes that it would be able to give a person strong power, knowing that it would win Parker the competition.
Morbius sets up a lab in his home, and "borrows" equipment from E.S.U. for his own research, including one of the neogenic devices, much to Felicia Hardy's disagreement. Michael explains to her that he is not only doing it for the assistant role, but also to find a cure for his hometown's disease. He also tells Felicia that he is studying vampire bats. After she has left, Michael uses the recombinator to further analyse the mutated blood sample, but one of his bats flies onto it while the recombinator is active, and as he tries to get the bat away from it it bites him, resulting in him mutating into a vampire-like creature.
Morbius feels the lust for plasma, and flies off to feed. After draining several victims of their plasma, Morbius is attacked by Spider-Man, before flying off. Spider-Man listens to a tape recorder of Morbius and discovers that he is the vampire, and realises that he and Michael are both now in the same mutation crisis, feeling guilty. Spider-Man suspects that perhaps Michael will visit Felicia, but when he visits her as Peter she berates him, thinking that he is trying to persuade her not to date Michael. However, after Peter has left, Morbius arrives and scares her, before Peter returns as Spider-Man and gives chase. After they fight, Morbius returns to his human form as the sun rises, and an unconscious Michael is found and taken to hospital, but flees again when taking on his vampire form.
Meanwhile, Peter's extreme pain continues, and while in his bedroom he suddenly sprouts four extra arms.