Hey Arnold Subliminal Message Laughing Grandpa

Hey Arnold Subliminal Message Laughing Grandpa is a screamer video posted to YouTube on October 30th, 2006 by user likekurdtcobain. The video shows a still image of Arnold's grandfather from Hey Arnold!, with a sound clip of his trademark laugh. Over the course of the video, his laughter is gradually slowed, so that the viewer can identify a hidden message. At 36 seconds, an eerily grinning young man appears with an ear piercing scream.

A variation exists where the face is replaced with that of Regan MacNeil with her usual scream.

Link
NOTE : The following video contains a screamer.
 * youtube.com/watch?v=hmU2Ydip0Bo
 * youtube.com/watch?v=GqLMTDW8Eoc& (alternative version)