The 2012 seniors at my high school released chickens and mice in different corridors. It was hilarious, if you caught one you had to "report to the front office." The 2013 seniors put cracked eggs on students' cars. The eggs sat there baking from 8 am till about 12, I was in class when a student came in late and went "guys, there's eggs on all the cars In the underclass men parking lot." Texts and tweets shot out and students ran to the parking lot, freaking out. The seniors didn't realize that eggs hurt the paint though so about 5 of them weren't allowed to walk graduation and 1 of them had charges pressed on them since some girl just had her car painted.