Curse of Destruction
Curse of Destruction is a spell cast by some monsters that inflicts continuous fire damage for a given period of time until the curse detonates, which presumably inflict additional damage (v2.05). Curse of Pain is a similar spell but it does not detonate. There are two ways to see if you are affected by this spell. First, there is a little icon above the "Achievements" icon in the menu bar that appears. Hovering over this icon tells you how many seconds are left before the spell terminates. Second, when you are under this spell, there are vertical orange circles appearing above your head. One of the monsters that uses this spell is Diablo.