Antlers

From the Introduction:

Santa Claus, the most magically potent creature on Earth, has finally succumbed to dementia. Aliens from outer space are infiltrating the Earth. Santa's reindeer have a brainwashing device which turns those aliens into Santa's elves or, if unsuccessful, garden gnomes. Only this device and reindeer's super powers stand in the way of total world domination. You can fly pretty fast, but have no hands.

There are two Santa's workshops, one in the North Pole, another on Korvatunturi hill between Finland and Russia.

And oh, it is Christmas Eve, and Santa seems to have forgotten...