[Houshalter]

I found an image which stimulates the edge detectors in people's brains, far more than a natural image. It tends to cause people to feel weird and not want to look at it, in a way they can't quite describe. And making the image flash and rotate rapidly made it far worse.

The image: https://i.imgur.com/Zihujue.gif

And it flashing: http://makeagif.com/i/hHzAiq