This apparently is cast upon you in Fear Itself. So far I only noticed it when you're being next to the giant hourglass for an extended period of time.
Be careful, as every new cast of this means a new tick of mana drain. I've lost about 10k mana in about 5 seconds once. I couldn't seem to escape the area where it was cast and thus I got hit multiple times in a very short period of time!
Edited, Apr 25th 2011 8:54am by CaldireFyreborn