PCs battling the hordes of Christmas, to push them back out of October and November, and back into the realm of December.
Santa wants to take over the holidays and your Players can play characters based on the other holiday creatures/people.
But it was too late. As you enter the chamber, the deformed mass of muscular tissue, eyes, and teeth, adorned with tattered red rags and white faux fur tufts is already feasting on the remains of Sir Lord Turkington. Thanksgiving is lost, but perhaps there is still time to save Halloween.