The world's smallest fly is so tiny you can hardly even see it. It's about the size of a grain of salt. A normal fly looks like a giant next to it.

But make no mistake: this tiny fly, which lives in Thailand, is no cute little thing. In fact, it wouldn't be out of place in an Alien movie. Its female has a sharp organ that she uses to lay her eggs inside other insects.

The fly, called Euryplatea nanaknihali, would be better named the zombie maker. It likes to lay its eggs inside ants. When the fly's eggs hatch, the babies move to the ant's head. There they feed on the muscles the ant uses to work its mouth. Then they eat the ant's brain, making it wander around brainless for a while. Then the fly larvae cause the ant's head to drop off. There they live happily for a few more weeks.