December 7, 2016 12:31 PM EST

In a new “Mad Lib Theater” skit on Tuesday’s episode of The Tonight Show Starring Jimmy Fallon, actor Chris Pratt and host Fallon have a blast re-enacting a very messed-up encounter between none other than Santa Claus and one of his elves.

Passengers star Pratt has no idea what he’s getting into as Fallon asks him for various words and descriptors to fill out their Mad Lib sketch, offering up suitably bizarre fillers (Name for an animal: “Pickles!” Adjective: “Demure!” One-syllable noise: “Uhhhh…”) to make the scene come alive.

The action really gets going at 3:36 in the video, when the two suit up in their respective holiday-themed outfits to act out the zany skit. Takeaway: Chris Pratt has an excellent Santa voice, and Fallon has been quite a naughty elf this year. Watch above.

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Write to Raisa Bruner at raisa.bruner@time.com.

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