opponent discard a card mtg Rules Text: Each player discards, 49 cards The Best Discard Cards In

Casting Cost: Card Type: Instant Card Text: Cast this spell only before the combat damage step

I think of Ghalta when I think of 12 Mana

Both these permanents can be abused a bit if you're able to proliferate the time counters, thereby keeping them on the battlefield longer than their prescribed number of turns

The other Duals are all from Revised: Bayou (GD) Badlands (GD) Plateau (PL) Plateau (PO) Savannah (PL) Underground Sea (NM) Volcanic Island (PL) High-End Reserve List Goodies Here's a great list of Reserve List cards to check out

Take this board state

Legality depends on the tournament format -- Two by Four can be legal in some formats and banned or restricted in others