Z50 Mana Gulper

Z50 Mana Gulper is an tinker enchant (only usable by players with Engineering) to gloves. It can be used to increase the mana gained from using a Mythical Mana Potion. As such, this is by no means a "free" mana potion - it will only work if there's a Mythical Mana Potion in the player's inventory to consume.

Source
This tinker is learned through Discovery; it can be randomly learned when making a Cataclysm-related item in Engineering.