Did you hear the one about the Swedish scientist whose laptop caused extensive blistering in a sensitive area? Turns out the professor had been typing for about an hour, notebook on his lap, occasionally experiencing a burning sensation. Later, the scientist noted irritation, which led to blistering and a trip to the doctor.

This sounds like a joke–but it actually happened, according to the BBC.

Overheating notebooks have been a problem for years. Some say the problem is about to get worse. Here’s a look at why some notebooks overheat, and what you can do about it.