Hands down, the nastiest tasting **** in the world is Malort. The official description:
Jeppson Malort has the aroma and full-bodied flavor of an unusual botanical. Its bitter taste is savored by two-fisted drinkers.
It's nasty tasting 80 proof liquor made out of some root I believe, that is wretched going down (drank straight in shots) and leaves a vomit aftertaste. By vomit, I'm being very literal here. The aftertaste reminds the palet of bile and stomach acid. It's a big biker drink, I can only imagine for the "bad ass" factor. "Yeah, he killed three men and he drinks Malort, too."
My parents had a bottle behind the bar for some friends who, for some unexplained reason, drank it. Even at the height of high school boozing and sneaking an inch from all the bottles, Malort would only be used as a prank: "Here, try a shot of this." and then watch their faces. A friend of mine from HS days just bought a bottle for his bar for the same reason
It's that bad.
Charon