Gluggagægir aka Window Peeper appears on the 21st and hangs around until the 3rd of january.

December 21 is when Window Peeper visits. This Lad was not as greedy as some of his brothers, he just liked to peep through the windows and sometimes nicked the toys that he saw. 

The tenth was Window Peeper,

a weird little twit,
who stepped up to the window
and stole a peek through it.

And whatever was inside
to which his eye was drawn,
he most likely attempted

to take later on.

Defenses against Window Peeper

Call the cops!