Squirrel: it’s more than an image, it’s inception.

Wrap your mind around this: Squirrel is a single file that renders as both HTML and a JPEG image. It’s a webpage. It’s an image. It’s Squirrel. If that doesn’t make your brain explode, the HTML version contains an img element that points to … you guessed it, itself. Recursion FTW!

To see how it works, view source on the HTML page.

Squirrel was created by developer Michal Zalewski, who has quite a few other projects as well, including the interesting-looking Skipfish, a web application “security reconnaissance tool.”