horsepiss

Bad beer, usually but not necessarily a homebrew. Characterized by a flat or nonexistent head and that telltale sour, rancid aftertaste.

Chuck took a swig of it and wished he hadn't. "This stuff is horsepiss," he grimaced, holding the cup at

arm's length as though its contents might be contagious.

Nuclear Horsepiss

Monster Energy drink.
Often found in the bladders of chernobyl horses.
That is where Monster harvests their produce

"This tastes like nuclear horsepiss"