Dispels one beneficial Magic effect from the caster and gives them X to Y mana. The dispelled effect must be a priest spell.
Consume Magic is one of the racial abilities available to Blood Elf Priests. It allows the priest to consume a priest buff on themselves in order to regain mana. This is very useful as part of your mana regen rotation.
This ability allows you to eat one of your own buffs, such as Inner Fire, Touch of Weakness, Power Word: Fortitude and so on in order to regain mana. In long mana intensive fights, this can be incredibly useful. The mana returned scales with your level as well.
Place a Rank 1 Inner Fire (or Touch of Weakness) on yourself, and then use Consume Magic. If the proper buff gets consumed, then you've just regained a good chunk of mana at almost no cost. However, it is advisable to not interrupt mana regen; instead, Consume Magic should be used in between casts.