Say It

Say It was a simple flash prank from around 2002 made by an unknown maker.

As the name implies, it is about the pop ballad "Say It" by the Kumbia Kings. It will start playing the song right away, while the lyrics slowly scroll up on a black screen, making it seem like a regular lyrics video.

After 12 seconds, shortly after the line "Say those three little words I can't wait to hear", a picture of Regan MacNeil from the 1973's classic horror movie The Exorcist pops up along with a loud scream.

Decompiling the flash reveals that the lyrics featured in this animation include the full refrain and half the lines of the first verse, even though the screamer pops up before the entire text has scrolled up. The excerpt of the song that is included in the file is also about ten seconds longer than what can be heard before the screamer.

The screamer was featured also known as 'Watch This!' on FunnyJunk.

joshtheblade
There's a poorly-made version of the flash which is created by joshtheblade. The excerpt of the song is longer than the original flash and it uses a different version of Regan's picture from the same movie, there is another screamer from the creator of the video with the same scream from K-fee commercials.

Abdul Rashid
There's another poorly-made version created by Abdul Rashid under the simple name of Scary prank. The song roughly ends at the same place as the flash version and again uses a different picture of Regan as its screamer.

Trivia

 * This is the first screamer to ever use Regan MacNeil, who would later be featured in The Maze.
 * This is the first lyric video ever posted on the internet before they were actually popular.

Links
NOTE : The following animation contains a screamer!
 * Emulated .swf: albinoblacksheep.com/flash/sayit
 * Raw .swf: web.archive.org/web/20050529210027/psy.msu.ru/illusion/jokes/sayit.swf
 * joshtheblade Version: youtube.com/watch?v=_bQlkXF6Uyw
 * Abdul Rashid Version: youtube.com/watch?v=TdQ-zx6bC2Q
 * Showcase video: youtube.com/watch?v=8Z8bG-ARjsA