The Mirror of Tragedy

I burned a small hole in my speakers with a shaving mirror yesterday. It was sitting on the desk as I was wasting time on the computer, and as the sun continued its predictable path across the sky, the reflected light from the magnifying side of the mirror was concentrated on to the rough covering of the speakers (I've really no idea what to call it) and a wisp of smoke went up from them. I quickly knocked the mirror away to discover a small, neat black hole.

Now that I look at it, there are also some strange lumps on the side of the monitor where it looks like the plastic has melted slightly. If I hadn't been in the room at the time it started burning I would have a delicately grilled computer by now. For now, I have put the Mirror of Death away at the other side of the room where it can't harm anything. It was bought recently at a car boot sale, the normal place for the acquisition of seemingly innocent items that have an immense amount of destructive power.