this spell was the difference between life and a wipe of my 2box when I had my 58 Monk duo'd with me (62 cleric) in BoT back in the day. If you had a serious twink monk lvl 58 like I DID, flagged for BoT, you would cast your Supernal Elixer on him after dumping this on him b4 a pull. This gave you enough time to land chain CH's/nukes after also landing a Mark of Karn on the mob.
For those of you who are even NOW leveling a cleric and find yourself approching 62, don't overlook this one! Coupled with a clestial b4 the pull and a "LANDED mark of karn", you can do things in zones that will amaze even yourself let alone the squishy tank you are duoing with :)