Horc comes from the Nordic word "Horcerer," who was a type of highly regarded Icelandic fighter in the 9th and 10th centuries, in part due to a psychotic state induced through the consumption of mushrooms, mead, and undercooked beef. During battle, the contents of the Horcerer's stomach would mix and form what the Nord's called "The Cauldron of Anger," which would foment and spew forth in a hot chunky spray. This precurser to today's pepper spray would immobolize opponents for several minutes, giving the Horcerer's companions time to maim or kill. Today, the word "horc" is used to describe any spewing forth of the contents of one's stomach onto another person or animal. Otherwise, the word "vomit" is appropriate.
Pablo was out of control at the cock fight last night, finally concluding the evening by horcing all over Pupenstein, the undisputed cockfighting champ from Honduras.