As far as comic book villains go, Red Skull has to be one of the baddest. Captain America’s rival is usually after the Cosmic Cube, and goes to great lengths to get it, but there was a time when he set his sights on another powerful object - the brain of Charles Xavier. Yes, really.
Red Skull first appeared in Captain America Comics #7, and has been an antagonist of the Star Spangled Avenger for over 50 years of publications. Red Skull was originally a Nazi under the Third Reich who fought against Captain America in World War II. However, at a certain point, Red Skull correctly suspected that the Germans would lose the war to the Allies. As a failsafe, he had Arnim Zola, a Nazi scientist, make a clone of him that would awaken decades later to attempt to conquer the world once again.
When the cloned Red Skull awakes in the modern day in Uncanny Avengers #1, he finds the United States in a similar position to that of Germany before World War II. Just as the Nazis used the Jewish people as scapegoats and tried to exterminate them, Red Skull plans to have the country turn on and eradicate the mutants. But to do it, he’ll need to use their own powers against them.
The recently deceased Charles Xavier has just been buried, so Red Skull sends a team to steal his corpse. Once they do, he cuts out Professor X’s brain and grafts the mutated part of it to his own, giving him Xavier’s immensely powerful telepathic abilities. It’s a grisly image to behold, especially for those who loved the Professor X character. To see his body defiled so soon after his death is enough to upset even casual X-Men fans. As can be expected, Red Skull uses his new abilities to wreak havoc. He begins forcing humans to kill mutants all over the world, an event that becomes known as the Red Riot, and even turns Genosha into a concentration camp. Even after he is seemingly defeated by Magneto, Red Skull only comes back as the even more powerful Red Onslaught.
Red Skull eventually loses after Scarlet Witch and Doctor Doom cast a spell which causes Professor X’s consciousness to briefly take hold of Red Onslaught, allowing the heroes to subdue him. The piece of Xavier’s brain was then surgically removed, taking away his telepathic powers, and the Red Skull is later killed by Captain America.