This is a pretty neat auditory illusion. If you listen to this correctly, you should feel a presence in the room with you.
Here's how it's done:
1) Only use headphones to listen to this video. It doesn't work with speakers.
2) Close your eyes and keep them shut throughout the video.
3) Try to block off any external distractions.
Here's the video:
It's about four and a half minutes long. Tell me what you guys think of this.
BTW, I'm not versed well in biology so I don't know whether this is common sense, but nonetheless I think it is pretty awesome.