If an opponent searched their library this turn, you may pay {0} rather than pay this spell's mana cost. Target opponent mills thirteen cards.

If three or more creatures are attacking, you may pay {U} rather than pay this spell's mana cost. Attacking creatures get -3/-0 until end of turn.

If an opponent gained life this turn, you may pay {B} rather than pay this spell's mana cost. Target player loses 5 life and you gain 5 life.

If a white creature is attacking, you may pay {B}{B} rather than pay this spell's mana cost. Exile target attacking creature. Create a token that's a copy of that creature. Exile it at the beginning of the next end step.

If an opponent had a green creature enter the battlefield under their control this turn, you may pay {U} rather than pay this spell's mana cost. Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

You may pay {1}{B} rather than pay this spell's mana cost. If the {1}{B} cost was paid, an opponent draws a card. Exile target creature or planeswalker.

If you control a commander, you may cast this spell without paying its mana cost. Exile target creature.

({B/P} can be paid with either {B} or 2 life.) Target creature gets -5/-5 until end of turn.

You may return two Islands you control to their owner's hand rather than pay this spell's mana cost. Tap all creatures.

Exile target nonland permanent. Its controller incubates X, where X is its mana value. (They create an Incubator token with X +1/+1 counters on it and "{2}: Transform this token." It transforms into a 0/0 Phyrexian artifact creature.)

If you control a commander, you may cast this spell without paying its mana cost. Counter target noncreature spell.

If you control a commander, you may cast this spell without paying its mana cost. Creatures you control gain indestructible until end of turn.

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost. Counter target spell.

If you control a Swamp, you may pay 4 life rather than pay this spell's mana cost. Destroy target nonblack creature. It can't be regenerated.

Destroy target nonland permanent. Its controller creates a 1/1 white Human creature token.

You may return an Island you control to its owner's hand rather than pay this spell's mana cost. You may tap or untap target creature.