Haunt of Fear #4

Eric is cheating on his wife, and Alan blackmails him into performing a radical new surgical procedure. Alan wants his head transferred to a healthy body, and they kill an innocent man to get that body. Eventually, Alan wants to change bodies again and, once again, he forces Eric to help him. But, finally, Eric can't take the guilt anymore. While Alan is nothing more than a (conscious) head on a table, Eric lets him die.