A little lepreauchan that sneaks into your room after you have a night of heavy drinking. He puts one foot on your chin and one foot on your nose and takes a wee crap in your mouth. Then cracks you in the head with his cane. This explains the bad taste in your mouth and headache when you wake up.
"Dude, you look like shit." "Yeah man, I got a visit from John Barleycorn last night."