Make Friends, Loved Ones Soil Their Pants

A popular scary prank to play on friends and family are these so-called observational things in which you're supposed to stare at something on a screen, only to have some horrific image suddenly pop up, accompanied by a blood-curdling scream.
I've been gotten twice by these things, but I got one via e-mail today that I knew right away was one of these seat-soiling pranks.
Of course, I feel obligated to pass it on. If you've got others, pass 'em along. I'll add as I get 'em.

For the one, set up the victim by explaining that there are 3 differences in the two photos. It helps to tell the victim you only got two, and that brings out the competitive spirit in them and makes them concentrate harder, thereby making the surprise more shocking:

http://members.home.nl/saen/Special/Zoeken.swf

On this one, you tell the victim that this is a car ad, and during the shooting a mysterious vapor, believed to be a ghost, can be seen near the car at one point. This gets their concentration powers flowing, and then AAAAAHHH!!!

http://video.google.com/videoplay?docid=-7481791789247956765

Here's a sick one involving Steve Irwin:

http://video.google.com/videoplay?docid=1945368730233675374

A very nice piece of prankery involving an alleged color test:

http://www.albinoblacksheep.com/flash/vision.php

Here's a whole collection of other ones:

http://en.wikipedia.org/wiki/List_of_computer_pranks

HAPPY HALLOWEEN!