Addams family haunted piano prank.

Note that this NOT a player piano, it’s just a regular old piano.
If you’re wondering how I did this, I got to the classroom an hour in advance and stashed a Bluetooth speaker inside the piano that was hooked up to my phone and waited. When the moment was right, I pressed play and let the fun commence.
(P.S. Yes I know the video angle is weird, my friend was filming this and didn’t notice until it was too late)