The Red Dot (tm) has turned out to be an unspeakably cruel tormenter of the cats.
It has them chasing all over the apartment for as long as they're willing/able to go after it. It also torments them by going places that they can't quite reach, wandering around in front of them just out of ambush range, suddenly disappearing without warning (only to reappear somewhere else), and exhibiting some rather dramatic speed and direction changes while it's being chased.
Of course, there's no point to being a cruel Red Dot (tm) unless it runs them up and down their cat tree a dozen times or more, leaving both of them laying on the floor panting as they try to plot SOME way to catch it.
Neither of them is showing any signs of losing interest in catching it, however.