The Mighty Thor (vol 1) #231 VF

When Thor and Hercules return to the surface from fighting "Fear," underground, they repair the hole that they made in the street. Then Sgt. Blumkenn informs Thor that a woman by the name of Jane Foster, has been asking for him. Thor's memory of Jane returns, and he rushes to the hospital where she lies unconscious. When Sif sees how much Thor is in love with Jane, she returns to Asgard in search of Odin, only to find out that Odin has disappeared and no one knows where he is.Meanwhile, back on earth, a faked seance, turns into a real contact with the past. The son of the medium is overcome by the spirit of the very first man, who was ever born - Armak. His body is transformed into that of a brutish Neanderthal. Apparently Armak is the personification of mankind's sheer brutality.The monster grabs the girl sitting across from him and crashes out onto the street, where he is met by Hercules. The Olympian attempts to free the woman, but is knocked down. Thor arrives on the scene and pretty much tells Hercules to sit this one out. Thor is angry that he had to leave Jane's side... so he takes out his frustration on monkey boy.Their battle takes them up into an elevator on the outside of a high-rise construction site. During the battle Hercules gets the possessed man's mother to call up to her son with a bull horn. When the caveman is distracted (more by his search for the girl than by his mother's call), Thor knocks him out of the elevator to his death.In the midst of the cracked pieces of concrete, Armak's visage changes back to that of the man he had possessed, who reaching for the pretty girl... dies. Hercules decides in his own mind that he plans on revealing the mystery behind this appearance of Armak.