Also wet toilet paper from the sink stuck on the bathroom ceiling real nice.
Oh geez, we had a math teacher in 7th grade who was very senior in the age group.
We did a total class spitball shooting one day. Almost everyone was shooting onto the blackboard (which had been cleaned before class).
How she did not hear that was a question. Eventually she noticed the chalkboard looked like the moon surface! She gasped and just sat at her desk and cried.
She went to the office and got the principal. The entire class got in trouble. (Nothing really happened) They picked a few to clean up.
Good times!!!