msem-instigator

Flying
{1}{B}, {T}: Destroy target creature that was dealt damage this turn.

Whenever you cast a white spell, target player loses 2 life and you gain 2 life.
Whenever you cast a green spell, put a +1/+1 counter on Corrupted Warlord.

Enchant creature
Enchanted creature gets -3/-3 and has “At the beginning of your upkeep, you lose 3 life.”

As Coveted Tower enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {G}, {U}, or {R}.

{1}{R}, Sacrifice Crackling Seaform: Counter target spell unless its controller has Crackling Seaform deal 3 damage to them.

Cradle of Corruption enters tapped.
Whenever a creature dies, put a creation counter on Cradle of Corruption.
{T}, Remove ten creation counters from Cradle of Corruption and sacrifice it: Put up to two target creature cards from graveyards onto the battlefield under your control. Activate only as a sorcery.

Crafted Coast enters tapped unless another player controls a land that could produce {W} or {U}.
{T}: Add {W} or {U}.

Flying
Cragstalker Eagle gets +2/+2 as long as you've cast a creature spell and a noncreature spell this turn.
You may cast Adventure spells and spells with Adventures from your hand as though they had flash.

Each player reveals their hand. Choose a creature card revealed this way. Its owner discards it.
{2}{B}{B}, Exile Cranial Violation and six other cards from your graveyard: Put target creature card from a graveyard onto the battlefield under your control. Activate only as a sorcery.

Target creature gets +X/+0 and gains trample until end of turn.

{1}{R}: Crashcaller Nereid gets +1/+0 and gains trample until end of turn.

Whenever you cast a spell for an alternate cost, create two 1/1 red Elemental creature tokens. (This includes “without paying its mana cost.”)
Whenever you cast a red spell from your hand, reveal the top card of your library. If that card has a lesser mana value, you may cast it without paying its mana cost. Otherwise, draw a card, then discard a card.

First strike
Whenever Creed, Eternal Straggler attacks, exile the top card of your library. You may play that card this turn, and that spell costs {2} less to cast.

Hexproof
Whenever one or more cards are put into your graveyard from anywhere, Creeping Hidebehind gets +1/+0 until end of turn.

Flying
Death knell — Put a flying counter on target creature you control. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

Crossfire deals 1 damage to each creature.
Quickdraw {2}{R} (When a creature you control blocks or becomes blocked, you may cast this spell for {2}{R}.)

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever Crowd Favorite extorts a spell, put a +1/+1 counter on Crowd Favorite.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Other creatures you control with distorted get +2/+2.

Reach
Scarecrow spells you cast cost {1} less to cast.

Flying
Cruel Fledgling enters with a +1/+1 counter on it if six or more cards are in your graveyard.

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.)

Primal {1}{B} (During your turn, you may cast this spell for {1}{B} instead of playing a land.)
Each opponent discards two cards.

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.

{1}{B}, Discard Crusher Claw: Target creature gains winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)