Man, I really hoped Peppermint Butler would be in the sleazy cantina. It makes sense for his character.
Or rather, a roundish figure in the backround in a black robe with a oddly bulging sack walking outside the place would have been great. No lines or even notice from the heros: just another guest who got what he needed.

On the other hand, it seems like the Halloween episode will be at a costume party and a whodunit. Which is weird. considering there has been two episodes with plots near this one. ( Okay, the last one may have been a strech.)

Anyway, costume guessing time!

Finn: Youngish Billy, with the fake beard and everything.

Jake: A wolf, why not?

Princess Bubblegum: A frankenstines monster. Why not? She already has the german down pat.

Everyones favorite Peppermint: Death. Paints over the red parts of his body with white paint, and finds a good skull mask. Or is it a skull?

Marceline : There is so many options for this one its not even fair. Shapeshifting has its perks when going to a costume party.

And the Lich shall be going as himself, perhapes in a King in Yellow type of deal.