Dumb High School Pranks - what was your favorite?

What was your favorite high school prank you pulled? Doesn’t have to be anything malicious or destructive, but something just funny that you guys pulled.

At my school, everyone was obsessed with zipties.. The chairs in all the classrooms had a lattice back, and the prank was to sit behind someone, and loop a ziptie between the chair and their belt loop, so when they stood up, they’d take the chair with them.

It turned into a game/competition, where you’d try and ziptie others while not getting ziptied yourself.

And the holy grail was if you could chain enough zipties to tie two people together.