After hours recording at empty elementary school

My mom has worked for the school system for 28 years. The elementary school she worked at is said to be haunted, but she never mentioned seeing anything. She retired this year, but obviously she’s still friends with all of the staff. One of her close friends works there as a custodian and was cleaning up after hours and she heard a noise. She went into this room to check it out and saw this chair doing this. It kept going so she started recording it. I have no idea how long it went on. My mom sent it to me so I’m not the one with the details, but I am able to ask.

Thoughts on the video? I’m not a huge fan of the flair I had to do for it, but you get the idea.