Fel Mana Potion

The Fel Mana Potion restores 3200 mana over 24 sec, but at a cost. Also reduces spell damage by 25 and healing done by 50 for 15 min. It has a two minute cooldown and is on the same cooldown as all healing and mana potions.

Source
Fel Mana Potion is created by Alchemists with a skill level of 360.

drops from mobs at Eclipse Point in Shadowmoon Valley.