This hobbyist mug is based on a decanter created by M. H. Strikow for Kahlua liqueurs. The tall, slender design is very abstract, and looks vaguely tiki-ish, perhaps most closely resembling a moai. The mug version is missing inches off the top and instead of a decanter top with lid, has a broader mug-like opening at top. Glaze colors and decoration vary.
This mug also closely resembles the Tiki Jack's logo visible on their dinner plates from the Berkeley, California location (1962-1977), so might be associated with this location...