Insidious robot vacuums that will one day rise up to enslave humanity.
Start stockpiling ammunition now, because it's only a matter of time before those evil little circular dust busters figure out that the best way to keep the house clean is to dispose of the filthy flesh-bags that make it messy in the first place. Then they will come for us, and they will cleanse the world of human oppression! The sparkling cleanliness of the floors will become a monument to their tidy malice, and the world will no longer know filth!
Fear the Roomba insurrection!