The South Park Gun Show was an event that took place in the Season Nineteen episode, "PC Principal Final Justice". The townsfolk stock up on guns to protect themselves from advertising.
Background[]
The gun show is presented as if it was a dog pageant show such as the "National Dog Show". For example, The judges referring to the guns as "gorgeous" and the judges using Dog breed Prefixes and the actual names of guns combined to refer to them (e.g. "Yorkshire 33mm", "Pekingese Glock 17").
Mr. Garrison, Caitlyn Jenner, Principal Victoria, Stan, Sharon, and Randy break-in and all announce that there are beings that want to gentrify the planet so that humans can't afford to live, and that someone's hiding Kyle Broflovski, to which all the audience members point guns at each other. Kyle then breaks in and announces that PC is the enemy (after being brainwashed by Leslie Meyers), and PC Principal then murders Leslie in front of everyone revealing she is a non-human, but an advertisement.