If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost. Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.
Whenever Marit Lage's Slumber or another snow permanent enters the battlefield under your control, scry 1. At the beginning of your upkeep, if you control ten or more snow permanents, sacrifice Marit Lage's Slumber. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.
As Mirrodin Besieged enters the battlefield, choose Mirran or Phyrexian. • Mirran — Whenever you cast an artifact spell, create a 1/1 colorless Myr artifact creature token. • Phyrexian — At the beginning of your end step, draw a card, then discard a card. Then if there are fifteen or more artifact cards in your graveyard, target opponent loses the game.
Until end of turn, up to two target creatures each have base power and toughness 3/3, gain flying, and become blue Illusions in addition to their other colors and types. Draw a card.
When Pondering Mage enters the battlefield, look at the top three cards of your library, then put them back in any order. You may shuffle. Draw a card.
"As the sky opened up, we ran for shelter. Halfway there I came to the sudden realization that, already soaked, there might be more to gain from experiencing the rain than running from it."
Enchant creature Enchanted creature gets +1/+1 and has flying. When a Ninja enters the battlefield under your control, you may return Smoke Shroud from your graveyard to the battlefield attached to that creature.
Return target creature to its owner's hand. Then that creature's controller may pay {U}{U}. If the player does, they may copy this spell and may choose a new target for that copy.
When Tribute Mage enters the battlefield, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.
When Urza, Lord High Artificer enters the battlefield, create a 0/0 colorless Construct artifact creature token with "This creature gets +1/+1 for each artifact you control." Tap an untapped artifact you control: Add {U}. {5}: Shuffle your library, then exile the top card. Until end of turn, you may play that card without paying its mana cost.