Spellsteal is a level 39 mage spell that steals a magic buff from a single target. The stolen buff will benefit the mage for up to two minutes, but never more than the duration remaining on the target from which it was stolen.
Spellsteal uses the dispel mechanic and is affected by dispel resistance. There is no known pattern to which buff Spellsteal will target. It attempts to steal a random buff every time. If a buff can be stolen, it will have a yellow border. Otherwise, you will get an error message, after attempting to steal it.
Sometimes a buff appears to have no practical use and is not worth stealing. However, if your party has no priest or shaman to dispel the buff, Spellsteal accomplishes the same thing.
Often overlooked, this spell can be extremely useful. For example, Valkyrion Aspirants in Valkyrion have a buff called Metanoia, which increases your damage output a lot, especially if you are a Fire mage.
Patch 5.1.0 (2012-11-27): The mana cost of Spellsteal has been increased to 21% of base mana for Fire and Frost mages, up from 7%.
Hotfix (2011-07-06):When using Spellsteal on a shaman, [Lava Flows] will no longer be given to the mage as a buff. The buff, however, will be removed from the shaman.
Patch 4.2.0 (2011-06-28): Mana cost has been increased by 100%.