There's nothing scarier than an ordinary scene being disrupted by the sudden realization that there's something sinister lurking in the shadows. I think that's why the Three Men and a Baby ghost was such a phenomenon - the movie was the very definition of ordinary, and yet you are struck with the image of a ghoulish child in the background. See if you can spot The Lurker in the advertisement above.
Here's another example of a Lurker - this time he's popping up on an old album cover. Can you spot the apparition of a drifter lurking in the shadows behind this celebration?
Ah, yes. There he is. Which one of the Rowdies will he drag to Hell this evening? Enjoy your party, Rowdies - enjoy it while it lasts. One of you will fall victim to........ The Lurker.