Wallmasters

Wallmasters haunt the ceilings of some dungeons. To defeat it, stay in one place until a shadow starts to form under you. Start running in circles, and the shadow will follow you.when the shadow stops, a horrible moan will fill the room, and the wallmaster will drop. Slash it with your sword to defeat it before it ascends to the ceilings again. If it catches you, it will take you back to the entrance of the dungeon.

   Or switch to first person mode as the shadow appears to make it leave you alone entirely ;)
   Some call it cheating, but it sure is a lot easier than running all the way back from the 
   entrance if you mess up.