Coldsnap

Flying, vigilance T: When target creature other than this creature dies this turn, return that card to the battlefield under your control.

Flying 1S: Target creature loses flying until end of turn. (S can be paid with one mana from a snow source.)

You may exile two green cards from your hand rather than pay this spell's mana cost. Allosaurus Rider's power and toughness are each equal to 1 plus the number of lands you control.

This land enters tapped. T: Add G or W.

Trample Cumulative upkeep G or W (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) When this creature dies, you gain 2 life for each age counter on it.

T: Target artifact creature's controller sacrifices it. That player may search their library for a noncreature artifact card, put it onto the battlefield, then shuffle.

Trample When this creature enters, you may search your library for an Aurochs card, reveal it, put it into your hand, then shuffle. Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.

Cumulative upkeep 1 (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Whenever this creature's cumulative upkeep is paid, it gets +1/+0 until end of turn for each B or R spent this way.

U, T: Target snow land becomes a 2/2 blue Elemental creature with flying. It's still a land.

Target attacking creature gets +X/+0 until end of turn. Draw a card at the beginning of the next turn's upkeep.

T: Remove target blocking creature from combat. Creatures it was blocking that hadn't become blocked by another creature this combat become unblocked, then it blocks an attacking creature of your choice. Activate only during the declare blockers step.

Flying Whenever this creature deals combat damage to a player, choose one — • That player returns a permanent they control to its owner's hand. • That player discards a card.

S: This creature gets +1/+1 until end of turn. Activate only once each turn. (S can be paid with one mana from a snow source.)

T: Add C.

Flying S: This creature gains first strike until end of turn. (S can be paid with one mana from a snow source.)

This land enters tapped. T: Add W or U.

Cumulative upkeep—Add R. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

At the beginning of each end step, each player gains control of all nontoken permanents they own.

Trample Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.

Destroy target nonsnow creature.

Flying S: This creature gets +1/+1 until end of turn. (S can be paid with one mana from a snow source.)

This artifact enters tapped. As this artifact enters, choose a color. T: Add one mana of the chosen color.

You may exile two blue cards from your hand rather than pay this spell's mana cost. Gain control of target noncreature spell. You may choose new targets for it. (If that spell is an artifact, enchantment, or planeswalker, the permanent enters under your control.)

Counter target spell. Recover 2UU (When a creature is put into your graveyard from the battlefield, you may pay 2UU. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)