Watch carefully

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

Video
It features several benign images, along with three poorly-drawn freeze-frames, before showing a screamer of an edited picture of Mona Lisa as an alien, accompanied by a godzilla roar sound effect is followed with a loud screech. The screamer occurs at the 31 second mark.

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