I remember this one very well because it made me laugh a lot! In the early 2000s we had classes in the computer laboratory and in a short time we learned everything that was not on the subject syllabus.
There were many pranks, but I have my favorite.
Using the NET SEND command, we sent messages to the computers in the front row of the room, generally occupied by the most "dedicated" students.
So we asked that the user should turn off the computer because it was heating up; or that he had accessed inappropriate websites and should appear in the principal's office.
There were a lot of laughs, I don't regret it!