So there are some bugs still floating around for world of warcraft that allows players to go under the game world and in turn they can move freely. This bug is still available in the current build of world of warcraft. Its over at taultunleashed if you are interested in reading about it.
Well someone has used that bug to now go to a new place in the game that isnt intended for world of warcraft cataclysm. The new location is called the twilight highlands. It has a ton of new stuff for play and something that people didnt think would be there.
In the video at around 3:20 you can see something that looks like sarlacc from the star wars universe. It has the giant mouth and tons of tentacles. The creature seems to be a major player in the upcoming wow cataclysm and might be deathwing in a form but thats not sure. Also there is speculation that this is one of the major dragons breeding grounds but once against no one is sure.
Anyways you can check out the video and see the exploit ina ction. Its pretty neat to see something that large in wow cataclysm. Its more than likely going to be end game content for the end of the expansion.