Peter begins to realize that someone is trailing him but doesn’t know it is detective Mac Gargan, employed by Jameson to learn how he obtains his Spider-Man pictures. However, Jameson ends the assignment after learning of scientist Farley Stillwell’s work in artificial mutation. He brings Gargan to Stillwell for superhuman augmentation that includes a costume with a bionic tail. Meanwhile, Ned Leeds departs to Europe for a Bugle assignment, leaving Peter hopeful that he still has a chance with Betty. Gargan, now called the Scorpion, sets out to catch Spider-Man and soon finds him at the Daily Bugle. The Scorpion bests Spider-Man in battle then sets out on a crime spree as the mutation process affects his mind. Dr. Stillwell tries to help him reverse the process but dies trying to follow the Scorpion up the side of a building. Jameson is mortified to learn that, in the Scorpion, he has created a menace even worse than Spider-Man. The Scorpion roughs up Spider-Man again, then sets his sights on Jameson. Spider-Man comes to Jameson’s rescue, rips off the Scorpion’s tail and defeats him. Jameson covers his shame by claiming credit and vowing to someday destroy Spider-Man.