A term used when someone is wearing really ugly pants. Referring to a Grandma's ugly couch, a person may say who shot the couch? Indicating that that person is wearing ugly pants. Who shot the couch can be used in many other ways. For example: Nice shirt, who shot the couch? and many more ways to express ugly things.
"Look at that guy, he's wearing camo pants."
"Nice pants, who shot the couch!?"