MAGIC: THE GATHERING
Counters target spell. At the beginning of your next main phase, add X to your mana pool, where X is the casting cost of target spell.
Among the strongest counter spells printed throughout Magic's history, Mana Drain not only gets you a traditional UU Counterspell, but also some extra mana for your troubles during the next main phase. It may be banned in Legacy but it's definitely powerful in Vintage and Commander decks.