There’s a ghastly sequence in which Jack and Callum interrogate Nick Kroll as a “death merc,” one of Gryla’s mercenaries, and are chased by a legion of monstrous snowmen whose Achilles’ heel is having their carrot nose ripped out. The witchy Gryla (a role even Shipka can’t inject life into) aims to steal a naughty list “the size of Rhode Island” and harvest the souls of all the bad-doers to galvanize her takeover of Christmas, or something like that.
And Gryla’s ex is the dark lord of Christmas and Santa Claus’s brother, Krampus (“Game of Thrones” star Kristofer Hivju in gargoylean prosthetics), another foe for Jack and Callum to face down — and for Callum to lose, and then win against, in a slapping contest in another of the film’s childish jabs at winky slapstick humor. It’s all slogging toward a sleigh-ride showdown in the winter night sky, reminiscent of the visually heinous boss levels of any Marvel movie, where CGI reaches an unintelligible pitch of PG-13-rated cacophony.