Some little kids see Santa as a scary monster, which is understandable since he's typically played by a large man wearing a fake beard, wig and hat, but Santa is the least scary man ever compared to Krampus.
As you may know Krampus is the Austrian keeper of the naughty list, a half goat half demon sent to punish wicked children by beating them with a bundle of birch sticks and dragging them off to Hell.
Grýla is an evil ogress from Iceland who snatches up naughty children and drags them back to her cave to be devoured, but she can only devour the truly wicked so kids who repent are set free.
She has given birth to at least 72 children of her own, most notably the 13 Yule Lads, who are like a twisted version of the Seven Dwarfs:
Sheep-Cote Clod: He tries to suckle yews in farmer's sheep sheds
Gully Gawk: He steals foam from buckets of cow milk
Stubby: He's short and steals food from frying pans
Spoon Licker: He licks spoons
Pot Scraper, aka Pot Licker: He steals unwashed pots and licks them clean
Bowl Licker: He steals bowls of food from under the bed
Door Slammer: He stomps around and slams doors, keeping everyone awake
Skyr Gobbler: He eats up all the Icelandic yogurt (skyr)
Sausage Swiper: He loves stolen sausages
Window Peeper: He likes to creep outside windows and sometimes steal the stuff he sees inside
Door Sniffer: He has a huge nose and an insatiable appetite for stolen baked goods
Meat Hook: He snatches up any meat left out, especially smoked lamb
Candle Beggar: He steals candles, which used to be sought-after items in Iceland