Watch carefully

watch carefully is a screamer video uploaded to YouTube by Kleanex on May 11, 2007.

The video instructs the viewer to watch carefully several benign images, as well as three poorly drawn freeze-frames flashing for a second. The viewer is instructed to keep a close eye on an image of Blue Angel Aircrafts in the final images. However, a picture of a Mona Lisa as an alien, accompanied by a T-Rex roar sound effect, is shown at the end, before the credits: "everything done by keenan."

Link
NOTE : The following video contains a screamer!
 * youtube.com/watch?v=ySAMz6aiQxs