msem-instigator

{T}: Target creature loses all abilities until end of turn. Exile Chochin the Silent Moth and that creature.

At the beginning of your upkeep, you may sacrifice another creature. If that creature had mana value 2 or greater, create a 3/2 colorless Horror creature token. Otherwise, create a 1/1 colorless Human creature token.
Whenever you create a creature token, you may pay 2 life. If you do, put a menace counter on it.

As Chromatic Interloper enters, choose two abilities from among first strike, menace, vigilance, trample, or haste.
Creatures you control with mana value 5 or greater have the chosen abilities.

Flying
{2}{U}: Until end of turn, target creature has your choice of base power and toughness 1/1 or 4/4 until end of turn. Activate only outside of combat.

Flying, prowess
When Chronosphere Sovereign enters, nonbasic permanents target opponent controls don't untap during their controller's next untap step.
When Chronosphere Sovereign dies, it deals 3 damage to each tapped creature you don't control. Destroy each tapped artifact you don't control.

Cleave deals 1 damage to each opponent and 1 damage to each creature and planeswalker your opponents control.

Create a 0/0 blue Construct artifact creature token. Put X +1/+1 counters on it, where X is one plus the total number of noncreature, nonland cards in your graveyard.

({T}: Add {R}.)
As Cloudpeak Spires enters, you may pay 1 life. If you don't, Cloudpeak Spires enters tapped.
Basic lands you control have “{T}: Add {R}.”

Flying, lifelink
When Cloudshaper Pilgrim enters, return target creature or enchantment card with mana value 3 or less from your graveyard to your hand.

({T}: Add {R} or {W}.)
Cloudsteel Summit enters tapped.
{1}, {T}: Add {R}{R} or {W}{W}.

When Cloven Forms enters, reveal the top three cards of your library. Put all creature cards revealed this way into your hand and the rest into your graveyard.
{5}{G}{G}{G}, Exile Cloven Forms: Put a creature card from or hand or command zone onto the battlefield. Create a token that's a copy of it, except the token isn't legendary.

{T}: Add {C}.
{1}: Clutch of the Coil becomes a 1/1 Snake creature with poisonous 2 until end of turn. It's still a land. (Whenever this creature deals combat damage to a player, that player gets two poison counters.)

Return target creature to its owner's hand.
Coalesce {4}{U}{U} (You may cast this from your graveyard for {4}{U}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

({T}: Add {W}, {U}, or {B}.)
Coastal Dominion enters tapped.

Poisonous 2 (Whenever this creature deals combat damage to a player, that player gets two poison counters.)
Coil Remnant has deathtouch as long as an opponent is poisoned.

Whenever Coincutter Agent attacks, you draw a card and you lose 1 life.

Flash
Enchant creature
Enchanted creature gets -2/-2 and can't block creatures you control.

When Coincutter Fence enters, starting with you, each player may create a 2/1 red Rogue creature token with “This creature can't block.” For each opponent that does, create a Treasure token.

Enchant creature
You may cast this spell from your graveyard if it targets a legendary creature you control.
Enchanted creature gets +2/+2 and has vigilance.

{T}: Add one mana of any color in your commander's color identity.

Lifelink
Partner with Imperator Valtasius (When this creature enters, target player may put Imperator Valtasius into their hand from their library, then shuffle.)
At the beginning of your upkeep, return target Soldier card from your graveyard to your hand.

{T}: Add {C}.
{T}: Untap target legendary creature you control. Activate only once each turn.

{T}: Add {C}.
{T}: Put a +1/+1 counter on each legendary creature and a loyalty counter on each planeswalker that you control entered this turn.

Enchant land
When Contested Discovery enters and at the beginning of your upkeep, untap enchanted land. You gain control of that land until end of turn.

When Convocation Elder enters, create two 1/1 green Elf creature tokens.
{1}{G}, Discard Convocation Elder: Create a 1/1 green Elf creature token. Draw a card. Activate only as a sorcery.