Sharks!

The screen saver on my laptop is a bunch of sharks swimming around. There are two different scenes. One is the open ocean, and one is a reef with a sunken pirate ship.
The sharks don't do anything other than swim around looking dangerous. Some of them swim quite fast, while others just languidly sweep back and forth.
Whenever the scene changes, the sharks start out swimming straight ahead and then peel off in different directions, like they're trying to give the impression they're not up to something.
But I know different.
You can pick what kind of sharks you want to have.
I picked a leopard, a tiger, a blue, a bull, a black tip, and two great whites.
The great whites worry me. They keep bumping up against the screen.
One of these days they're going to come right through it.
If I ever disappear, check my screen saver.