9 Terrifying Diseases That Turn Your Life Into A Horror Movie

4. Alien Hand Syndrome

It's a classic of the genre. Being out of control of one's own body is a petrifying prospect because there's nowhere to run, which is why you'll find it in everything from Harry Potter to The Exorcist.

More petrifying is that, not only is it possible in real life, but there have also been cases of people with Alien Hand Syndrome being attacked by their out-of-control limb. Some even find their alien hand undressing them against their will.

Alien Hand Syndrome can be caused by damage to the frontal lobe or the severing of the bridge of neurons that connects the two different sides of the brain, known as the corpus callosum. This is sometimes done on purpose as a cure for severe epilepsy. It does stop the seizures, but you also run the risk of making an enemy in your own body.