With the National Institute of Mental Illness reporting that only 1.9 percent of the U.S. adult population lives with extreme phobias, does it really make sense that Dr. Rudy Vincent would have two patients with cases of debilitating fears? Spoilers for Episodes 1-3 follow. Possibly not. Dr. Rudy may be a clown on AHS: Cult. Although he's apparently assisting Ally as her therapist, the opening scene of the Sept. 19 episode, "Neighbors From Hell," casts some major suspicion on him. With his patient Rosie working with him to conquer her fear of coffins — and then the clowns promptly placing Rosie in a coffin to die alongside her husband Mark —Dr. Rudy (played by Cheyenne Jackson) sure seems to be part of Kai's crew.
His phone session with Ally in "Neighbors From Hell" isn't a definitive sign that Dr. Rudy is manipulating her under the pretense of helping her — although he definitely is annoyed by Ally, has a menacing vibe, and plays with some smiley face buttons (which is the mark of the killer clowns). But his time with Rosie feels like proof that he's involved with Kai. Based on the opening of the third episode of the season, it wouldn't be surprising if Cult later reveals that Dr. Rudy made a pinky pact with Kai and that he uses his profession to alert Kai to people suffering from extreme phobias so that Kai can then exploit their fears to gain power.
As for if Dr. Rudy also moonlights as a clown, that would make for a great reveal. There appear to be four male clowns so far — the one who wears a mask that has three faces, the orange-haired clown, the green-haired clown, and the one with the exposed brains. While I had previously thought Evan Peters' Kai was the clown with the three faces, there's evidence he could be the clown with the orange hair who went into Ozzy's room during the Sept. 12 episode, "Don't Be Afraid Of The Dark." If you take the orange-haired clown out of the running, the tallest clown seems to be the one who wears the mask with the green hair. Due to their heights, Jackson's Dr. Rudy and Billy Eichner's Harrison are the most likely candidates to be that particular one.
A theory worth considering — thanks to his beekeeping hobby — is that Harrison is the masked man spraying chemicals in the neighborhood. That then leaves Dr. Rudy to be the green-haired clown. Of course, the clowns could change masks or pull double duty as Kai sees fit, but if this theory is true, that means Dr. Rudy has been tormenting Ally since the very first episode in the grocery store. It's particularly cruel since she discussed her coulrophobia (fear of clowns) to Dr. Rudy thinking she was in a safe space during the premiere episode.
Another clue that Dr. Rudy is the green-haired clown is that when the blackout occurred in Episode 2, that was the clown to first show himself to Ally. He escalated her fear, which eventually led her to shoot her employee Pedro. As Dr. Rudy had already made a visit to her home during "Don't Be Afraid Of The Dark" to check on her well-being at the behest of Ivy (sureeee), and knew Ally had a gun, perhaps Dr. Rudy actually made two house calls to Ally's home.
While there is a fan theory on Ranker that Dr. Rudy Vincent is the mastermind behind the cult and Kai is his puppet, I still believe that Kai is in charge. But after "Neighbors From Hell," it's clear that Dr. Rudy shouldn't be trusted and is in cahoots with Kai in some capacity. Whether that includes clowning around with Kai is yet to be revealed, but either way — Sarah Paulson's Ally seems completely unaware of Dr. Rudy's sinister intentions. And as one of Ally's confidantes and as an alleged professional, you can be certain that he's going to help push her over the edge in the name of Kai.