Back when the Tickle Me Elmo was the hot Christmas toy, I was in a Walmart when a pair of teenage boys went through an aisle packed with said Elmos and set them all giggling at once. It was pretty funny…
When I worked retail in a department store, the staff of the department I worked in (better men’s sportswear) would dress one mannequin in the worst clothing in the department. Just the one mannequin, not all of them.
Some of the stories from posters are funnier than the fabricated story in the OP. I am going to resist the urge to do any of these things though I love the slapstick innocence of setting off a cacophony that is outside your hearing range. I wonder if dogs and cats suffer through mistakes we never knew we made.