When you see it

When you see it, also known as shitbrix, mind games, and Mind Fuck, are another type of screamer created in around 2008. The creator who started it remains anonymous.

The concept is pretty similar to What's Wrong; the objective is to get the viewer to look closely at an image that appears normal at first glance and to claim that upon closer inspection, they will find something frightening or disturbing. But when the viewer is focused on the image, a screamer will appear on the screen and scare the viewer. These screams generally come in the form of animated GIFs that are meant to be still imaged.

Links
NOTE : The following animations contains screamers!
 * s-media-cache-ak0.pinimg.com/originals/68/a9/a0/68a9a0e4730a2886a4fc273392f685c3.gif
 * i3.kym-cdn.com/photos/images/newsfeed/000/237/388/289.gif
 * Collection of Pictures: shitbrix.com