I had this idea in my weblog a while back:
If your pointer lies motionless for a certain period of time, a little animated troll would sort of poke its head in from offscreen, and then make a b-line for your cursor. It would appear as if it the screen were the ground it scampers on. When it reached the pointer, it would reach up as if the pointer were above it, snatch it down with both hands, and run off with it. It would try to hide from you. If you wiggled the mouse, the cursor would wiggle in his hands, but he'd have a pretty good grip on it, so you'd have to give it a good wiggle to wriggle it loose. He'd then look scared and run off.