Among the stuff dug out of the attic and basement for the yard sale has been a couple of Furby dolls, which turn out to almost kind-of work for the most part. With the new batteries put in it turns out at least one of them will suddenly pop its eyes open and start muttering chipper things in Furbish, the sing-songy language created by JRR Tolkein, and then keep at it a couple minutes until it gets bored and goes back to sleep for hours and hours.
This made us realize: when the thing was put up in the attic years ago, with batteries in, it was probably doing the same thing, waiting for a random moment and then popping open its servo-controlled eyes and wiggling its slightly lopsided ears and demanding attention in one of several dozen phonemes, and then falling back into a silent wait that might end without warning.
So, now we can finally explain why the bats in our attic were having nightmares all those years. Good to know.