Infest - Spell - World of Warcraft
You can drop off Infest from you by canceling hp buffs after you got it.
It's easy with some /cancelaura macro. After that fast rebuff.
It's make encounter easier so you don't need so many healers.
It is very possible that Paragon killed him on 25hm because they used it and took 1 dps more (just 5 healers) to don't hit enrage.
It's very usefull both 10 and 25 HM.
e;
http://img2.imageshack.us/img2/7792/dvui.jpg
Screenshot from Paragon (notice aura macro on bars and 59 minutes left stamina buff on 10%)