First appeared in Journey into Mystery #99 in 1963 and was created by Stan Lee and Don Heck. Dr. Calvin Zabo was a medical researcher who became obsessed with the experiment in Strange Case of Dr. Jekyll and Mr. Hyde to the point that he began robbing his colleagues in order to fund his replication of the experiment, leaving them suspicious. His colleagues' suspicions caused Dr. Donald Blake not to hire him at a hospital. Zabo created the Hyde Formula and swore revenge on Dr. Donald Blake, but was beaten by Thor, so the former began committing robberies disguised as Thor.read more
