My friends are temporarily house-sitting a cat. The cat met the monster yesterday. I expected to find out the dog or a vacuum cleaner is the scary item but it is the Roomba. Have you met the Roomba? It is about the size of a dinner plate, it is self-propelled and it is a self-guided, pretty smart vacuum cleaner. For you, a human being, it may be pesky but it is probably not terrifying but for a feline predator, it is.
https://www.irobot.com/en_US/roomba.html
We tried explaining to Tabby that it is not dangerous but speaking wasn't very effective.
Another neighbor has an impressive Wisconsin fall tree:
