When you see it, or mind games, are a common type of screamer. The concept is pretty similar to What's Wrong; these have as a goal to make the viewer look closely at a picture that seems normal at a first glance, by claiming that upon looking closer you will find something scary or disturbing. However, on some occasions, when the viewer concentrates on the picture, a scary image will pop up. These screamers usually take on the form of animated GIFs that pretend to be still images.
NOTE: The following animations contains screamers!