This is a mug shaped like the head of Pazuzu. Pazuzu is the main antagonist in The Exorcist horror novels and film series, created by William Peter Blatty. Blatty based this on the actual Mesopotamian demon.

From Ohana Is Dead:

"In ancient Mesopotamian religion, Pazuzu was the king of the wind demons and the son of Hanbi, god of evil. Although Pazuzu is considered an evil spirit, he was called upon to ward off other malicious spirits, protecting humans against misfortune and plague.

We took an ancient Mesopotamian artifact and turned it into a relic of our own! Standing 6 inches tall and holding roughly 24 fluid ounces of your favorite tropical treat, Pazuzu is sure to exorcise your thirst and send your head spinning.

Art by our homie, Very Good Tiki (Tiki Nava) and, produced by good friends, Munktiki Imports."