Ghostly Business

So I'm not sure if it's ever come up in our impromptu conversations, but over the years there's been some activity of a ghostly type at Rose Manor, aka the House of SoulSlam. Weird things mostly.

Anyway, Friday, your amiable host arrived home a bit early and found a giant mirror on the couch. It usually hangs on the opposite wall. So I test the BWSS and ask. She responds that the YSSS heard a "thump", came into living room to see what's what and found this mirror "hanging" by one anchor (a screw). There's a small table underneath that supported it.

So I take a look at mirror, expecting to see clasps on back damaged. Nope. Check the anchors aka screws. Still in the wall. The one it came off of (jumped?) had a little play but seemed fine. So we re-mount mirror and all's good.

Now what I can't seem to figure out is how a clasp made it over the side of a fairly large machine screw that has a pretty big profile. Nobody in the LR at the time. It hadn't been taken down for well over a year (BWSS painted the wall a lovely plum color). So what happened?

Ghost?