You're being watched.

Stimulating a certain spot in the brain with electricity may make people feel like a shadow person is hovering nearby.

Doctors in Switzerland documented the startling sensation in a 22-year-old woman with no history of psychiatric problems.

The researchers stumbled upon the discovery while evaluating the woman for epilepsy surgery.

During the checkup, the doctors electrically stimulated the left temporoparietal junction in the woman's brain.

Out of the blue, the woman reported having "the impression that someone was behind her," write Shahar Arzy, MD, and colleagues in Nature. Arzy works at the Laboratory of Cognitive Neuroscience at the Ecole Polytechnique Federale de Lausanne in Lausanne, Switzerland.

So what does the TPJ 'do' again? I feel like it's one of those mysterious brain areas that 'lights' up (I really don't like that word for some reason) in a bunch of different tasks.
I guess I could stop being lazy and just look it up - but hey! that's what the comments section is for. Anyone want to fill me in?

Here's the nature news version of the story.