We already know that Grey's Anatomy Season 10, Episode 7 (entitled "Thriller") wouldn't disregard its Halloween airdate — since zombies and werewolves have already been cast — but now we have a few more details about the hair-raising episode, thanks to the following synopsis from ABC.

"It's Halloween, and the doctors of Grey Sloan Memorial are hit with a barrage of spooky patients, which affects their own plans and puts one doctor's well-being in jeopardy. Meanwhile, Derek [Patrick Dempsey] collaborates with Ben [Jason George] on a new surgical technique, and Richard [James Pickens Jr.]  angers Bailey [Chandra Wilson] when he asks a second-year resident to perform his next surgery, on a special Halloween episode. Jason George (Mistresses) guest-stars."

Did you hear that? Ben Warren is back! His guest-starring gig means that “Booty Call Bailey” will, at long last, be reunited with her long-distance hubby — and that we viewers will be reunited with Jason's billion-dollar smile.

And if Ben is collaborating with Derek, it must mean that he's doing pretty well as a surgical intern down in Los Angeles, no?

Furthermore, in whose hands is Richard placing his life? Who in the cast is a second-year resident? As far as we know, all the main cast members play either attendings or interns. Any ideas?

Are you ready for this eerie installment of Grey's Anatomy? Give us your thoughts below.

Dan Clarendon is an assistant editor at Wetpaint Entertainment. Follow him on Twitter and Google+!