Revenge is human nature, even for psychics. Eric Stoltz will guest on Medium on Feb. 28, playing Sonny, an escaped serial killer bent on getting the person who helped put him in prison: Allison Dubois. Sonny's actions are even more menacing because he has the same psychic gifts as Allison. "He's able to dream lucidly and see things that are occurring," Stoltz tells TV Guide. "He's the dark side of the coin. Allison uses her abilities and talents for good purposes, and my character is much more interested in doing dastardly things."

At press time, Stoltz was saying that, "We keep getting different endings!" so he can't say for certain if he'll be returning to the NBC drama. The episode is unique in that "the threat is more personal to Allison. Usually she's helping others, but here she has to help herself." - Reporting by N.F. Mendoza