Senior Prank
About
High schools around the country,and probably even beyond often have their senior class participate in what's known as a "Senior Prank".
These usually consist of often harmless pranks in which many students will dress a certain way or do something at a specified time, but have also been known to escalate to causing damage to schools and even causing closures.
Sage Creek has had 2 so far and both were relatively harmless, with the Senior Prank 2018 being commended for it's honorable base.