1 you could create a something that stinks so bad like fish and stick thim in to the air vents causeing a massive stinch

2 you could tack your vary own mascott and frame a diffrent school for doing it haveing the student body getting pissed of and wanting to get back at then soon to find out that the other school had done nothing in the first place

3fill lots and lots of water balloons and began throwing thim at the teachers haveing a fun time getting wet

4 finnallly you could ask all the guys and girl for guys take thir condoms and the girls to still thir bros and fill thim with toth paste and throw thim every were at people freaking thim out giveing a vary gross feeling

but i do have to warn you the best thing to do would be to come up with some safe fun prank a come up with a way it wouldnt hurt any one or ruin the school and then get it approved by the dean or principal some one cool but dont tell anyone else you got it aproved cause other wise you could be suspeneded expeled fined and jailed

they can go upstairs but cant go down