Heroic: Dark Heart of Pandaria

Still to this day the Mouth of Horror blob is causing people problems.
This mob is in the mining tunnel and has an uninterruptible fear.
The fear causes you to run into the walls of the tunnel and fall through the map.
You will then be disconnected and every time you log in, you will fall and DC again even though you can see a pile of your dead bodies from not releasing.
You either need to wait 30 minutes to an hour for the game to realize you are DC'd and send you out of the scenario or log into another character and choose support and the character stuck service.
You will be redirected to the Blizzard website to perform the service.
You can prevent this by pulling him out of the mining tunnel, but if you get feared into a rock or hill just right you might also fall through the map.