One of nature's darkest mind-control stories happens inside a simple praying mantis. 2 What you're seeing isn't just a bug - it's a host being controlled by a parasite known as a horsehair worm. These worms grow and mature inside insects, silently feeding and waiting until the right moment. When it's ready to leave, the worm doesn't escape normally. It rewires the mantis's brain. The insect suddenly seeks water - something a healthy mantis would never do. And once it reaches it, the parasite for