The yule lads
Now that the hipsters have ruined Krampus for everyone (“About 20,800,000 results” in Google), I predict that the fad for Xmas 2016 will be all Gryla and her brood of Yule Lads: Sheep-Cote Clod, Gully Gawk, Stubby, Spoon Licker, Pot Scraper, Bowl Licker, Door Slammer, Skyr Gobbler, Sausage Swiper, Window Peeper, Door Sniffer, Meat Hook, & Candle Beggar. Gryla is a child-eating ogress and the Yule Lads, her sons, each come on a different night (December 12-24) to cause mischief. The Lads seem pretty innocuous for trolls, but since most of them are stealing food in the winter in Scandinavia, when freezing and starvation would be very real dangers, their antics were probably pretty scary back in the day.
Anyway you have eleven days to prepare for their onslaught.
Gryla catching lunch
Dimmu Borgir, one hopes, is working yuletide concept album on them. (Dimmuborgir is supposedly the home of Gryla and her family.)
Swords & Dorkery 
Never heard of those demonic creatures, I shall investigate more!
I was just thinking of using them in my Christmas session of D&D =) gotta figure out the stats though. Any thoughts are welcome.