Like other classics such as WHO WAS PHONE? and TEH DAY OF ALL TEH BLOD, this is a legendary troll pasta. An all-caps jewel in the community. The phrase "AND THEN A SKELETON POPPED OUT" is often used to point out that the ending of a Creepypasta is predictable or just downright shitty.
The Terrifying Pasta
WARNING: IF YOU HAVE A HEART CONDITION DO NOT READ THIS. YOU WILL DROP THE FLOOR, FLOPPING LIKE A FISH, WHILE CLENCHING YOUR HEART SEEING AS YOU ARE HAVING A HEART ATTACK. ALSO: IF YOU HAVE A SENSITIVE ANUS DO NOT READ THIS; THE BRICK YOU SHAT WILL BE PAINFUL.
A FEW YEARS AGO A MAN WAS WALKING DOWN A ROAD BECAUSE HIS CAR BROKE DOWN AND HE SAW A CAR COMING UP BEHIND HIM SO HE STUCK OUT HIS THUMB TO HITCH HIKE AND THE CAR STOPPED AHEAD OF HIM. HE RAN UP TO THE PASSENGER SIDE AND OPENED THE DOOR. WHEN HE OPENED THE DOOR A SKELETON POPPED OUT
How to rip off this pasta to make your OC horrifyingly good
This is less of pasta and more of a story ender. However it has been used so many times that it is as close to being creepypasta as a meme can be. To use it, end your story with "and then a skeleton popped out." Instant horror story.