Let's see... 'American Horror Story: Asylum' has covered creepy kids, mutant cannibals, a serial killer, aliens, secret Nazi doctor experiments, angels, demons -- are we forgetting anything here? Oh wait, a killer Santa!

Ryan Murphy and Co. really like to emulate the horror films that clearly inspired the show -- with Thredson, for instance, we get a little Leatherface/Norman Bates/Hannibal Lecter action, which is the perfect example of the Bonkers Blender (copyright just now when I made it up) of ideas that Murphy and his writers come up with. And with Thredson, we see how so many ideas can be emulsified into something really great.

That said, I'm not sure Ian McShane's killer Santa Claus works. His motives are burglary, his hate of Christmas, rape (okay, why not?), and general terror. He seems to only exist because it's December and the writers really want to run this Christmastime thing into the ground. McShane is good in the role -- no mistake there -- but he's such a hodgepodge of vague motivations that he feels only partially-drawn. It's as if Murphy watched 'The Dark Knight' and thought he could do a mash-up of the Joker and 'Silent Night, Deadly Night.' Silent Night, Dark Knight? Oh god, I think I just found out what it feels like to be in Ryan Murphy's brain for a moment. Send help.

Here's what does work: Lily Rabe continues to be an absolute delight in her role as the possessed Sister Mary Eunice, displaying a gleefully sinister calm as Jude re-enters the facility and reveals that she knows who Mary Eunice really is, showing her cold authority when Dr. Arden asks her to handle the Irish cop who shot Grace and is contemplating confessing to his crime, and playing the role of puppet master as she gifts our killer Santa with his costume so he can take care of that sad Irish cop and Sister Jude for her.

And we've also seen how clunky exposition can be a little less so when delivered from the possessed Mary Eunice -- as the devil, she's privy to the sins of everyone in Briarcliff, and through her we learn the story of how killer Santa came to be: a disenfranchised young man, he stole a loaf of bread and upon being jailed for his petty crime, he was raped by five inmates... on Christmas. Yeah, that'll make anyone hate Christmas, and even with that information, I still think his motives and designs are so vaguely inspired that they fall short of some of the other great mash-ups we've seen Murphy attempt visually and thematically. Though I have to say watching killer Santa chew a guy's face in that flashback made the otherwise needless explanation of how he came to be locked in solitary worth it. And he's such a lady killer, too: "What do you say we blow this pop stand, go savage a few elves, and then suck on each other?" You got it, killer Santa.

Who knew this week would be such a laugh riot, though, right? Dr. Arden telling the story of the ruby earrings he gives to Mary Eunice was the funniest this show has ever been. They belonged to a Jewess who complained of stomach pains (stop me if you've heard this one), and when he followed her one day to get a stool sample after she used the facilities, he found her digging through her own waste to retrieve the earrings. The little face-shrug Lily Rabe gives as she continues to put the earrings on anyway is priceless. I was concerned for a moment that Arden might be fully embracing Mary Eunice's devil, but the idea that he loves Mary Eunice for the very purity he lacks, and the way the show is examining the varying degrees of evil is fascinating.

Everyone loves Mary Eunice's purity -- Jude sees that the devil is using it as a shield; Arden admires and craves it almost carnally, delighting in that which he neither has nor can possess; and Jude is so fond of her gentle soul and feels the need to protect it from evils she knows too well -- evils within herself. And it's that highly-coveted purity that finally unites Arden and Jude together to fight the devil within her... Or not. Unfortunately, not. Arden pulls a bait and switch and gets Jude back to the asylum just so Mary Eunice can lock her up in a room alone with bad Santa. All that awesome build-up to the idea that Arden and Jude would team up to free Mary Eunice's soul was for nothing. And even worse, it negates that amazing scene with Arden and the earrings and erases any depth they spent so much time building for his character this week. Not even killer Santa saying he'll chomp down on Sister Jude's "dry loaf" (add that to the pile of zany euphemisms for vagina this show has given us) with his rotting teeth can save this lame turn of events. As expected, Jude bests evil Santa, keeping her around to continue fighting Mary Eunice.

But there's another team-up afoot: Lana and Kit are locked in the same portion of the asylum, and that now Kit knows that Thredson is the real killer, it's up to the pair of them to do what they've been doing all season: try to escape and get the truth out there. So basically, their stories haven't really changed, and just when I found myself longing for the days when Lana was locked up in Thredson's basement, he appears for a little chat with our favorite intrepid reporter about using her face for a new mask. And things get really interesting when Kit shows up to stop Thredson and convinces Lana that they need him to save Kit from a death sentence, so naturally they lock Thredson up for safekeeping until they can figure out what to do with him.

Oh, and P.S., guys: the aliens are back and visiting Dr. Arden now, in case you forgot there are aliens.