msem-instigator

Crumbling Necropolis enters tapped.
{T}: Add {U}, {B}, or {R}.

({T}: Add {B} or {R}.)
Whenever Crumbling Precipice becomes tapped, you lose 1 life unless you control two or more basic lands.

Crumbling Shrine enters tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)
{T}: Add {G}.
{2}{G}{G}: Crumbling Shrine becomes a Nymph creature. (This effect lasts indefinitely.)

Crumbling Vestige enters tapped.
When Crumbling Vestige enters, add one mana of any color.
{T}: Add {C}.

Creatures you control get +4/+4 and gain trample until end of turn.
Coalesce {8}{G}{G} (You may cast this from your graveyard for {8}{G}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Trample

Up to one target creature you control has base power 4 until end of turn. (Then exile this card. You may play the land later from exile.)

Assault {3}{G} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Crushclaw Pulverizer assaults, you may destroy target artifact or enchantment.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Crusher Beetle can't be blocked by more than one creature.

Choose one —
• Destroy target artifact.
• Crushing Grip deals 2 damage to any target.

Death knell — Put a trample counter on target creature you control. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)
Sacrifice a creature: Put a +1/+1 counter on Crushing Victor. Activate only as a sorcery.

When Crux Pinnacle enters, for each color, exile up to one target permanent of that color until Crux Pinnacle leaves the battlefield.
Whenever a player casts a spell, if there are five or more spells on the stack, you win the game.

{T}: Add {C}.
{X}: Crypt of Myriad Fates becomes a copy of target creature card with mana value X or less in your graveyard until end of turn, except it's 2/2 and a land in addition to its other types. Activate only outside of combat.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
{1}, Discard two cards: Unlock Cryptic Fragment. If the revealed card is a basic land card, put it into your hand.

Cryptic Reef enters tapped.
{T}: Add {G} or {U}.
{2}{G}{U}, {T}, Sacrifice Cryptic Reef: Draw a card.

When Cryptic Waypoint enters, create a 1/1 blue Scout creature token.
{T}: Add {G}, {U}, or {R}.

{2}{G}: Cryptozoologist voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Cryptozoologist phases in, you may put a creature card from your hand onto the battlefield until Cryptozoologist leaves the battlefield. (It returns to your hand if it's still on the battlefield.)

Whenever you sacrifice a permanent, scry 1.
{1}, Sacrifice a nonland permanent: You gain 1 life.

({T}: Add {U} or {R}.)
Whenever Crystal Cavern becomes tapped, you lose 1 life unless you control two or more basic lands.

Put three +1/+1 counters on target land. It becomes a 0/0 colorless Elemental creature with haste that's still a land.
Orchestrate—Sacrifice a land. (You may exile this card from your hand anytime you could cast a sorcery for its orchestrate cost. When you next resolve a spell, you may cast this from exile without paying its mana cost.)

Crystal Garden enters tapped.
{T}: Add one mana of any color. You can't spend this mana to cast a creature spell.

{T}: Add {C}.
{T}, Pay 1 life: Add {U} or {B}.

When Crystal Vision Abomination enters, create a 1/1 blue Elemental creature token with flying.
Whenever an Elemental you control attacks, that creature gets +1/+0 and first strike until end of turn.

When Crystalline Golem enters, choose a color. You gain 1 life for each permanent of that color you control.

Equipped creature gets +2/+1 and has menace.
Whenever equipped creature deals combat damage to a player, they sacrifice two permanents.
Equip—{2}, Sacrifice a creature.

Escalate {R}{R} (Pay this cost for each mode chosen beyond the first.)
Choose one or more. You may choose the same mode more than once.
• Culminating Chaos deals 2 damage to each creature and each planeswalker.
• Exile the top two cards of your library and add {R}{R}. Until end of turn, you may play those cards.