Any hypothesis as to what the hell is going on in my house?

Something weird is gong on. Yesterday I was in the kitchen and I heard a very LOUD thumping coming from up stairs, almost directly above me. I paused and cocked my head, and the dogs ran to the stairs and peered up. I asked Rick, who was in the other room, if he’d heard it but he was all engrossed in the game and said he hadn’t, so I just shrugged it off. I don’t believe in ghosts. Except for one ghost who lives upstairs, and that is not his MO. He’s more polite than that.

Rick’s office is up stairs. This morning he came down and said, “Did you hear that?”
I said, “No….”
He said he was sitting there when suddenly there was this loud thumping, like some BIG something, his size, was storming across the rafters! The coffee in his cup, which was on the desk, was running concentric circles, and the antenna on this electric toy truck was wiggling back and forth! He said it was like an earthquake.
I said, “Well, go look!”
He said, “I HAVE! I looked all over up stairs!”
I said, “No! Go look in the attic!”
He said, “Hail no! I’m not looking in the attic! Whatever it is, it’s HUGE!”

Should I call 911? Dispatcher “Yeah, it’s the possum lady. Yeah. The one whose kid got stuck in the mailbox. Says there’s a ghost in her attic, wants animal control to come get it.”