msem-instigator

Whenever another creature or enchantment you control enters, you gain 1 life.
{3}{W}{W}, Pay 5 life: Castigated Sister becomes a 5/5 Angel Horror with flying. (This effect doesn't end at end of turn.)

Casualty of War deals 4 damage to target creature or planeswalker.
{2}{R}{R}, Exile Casualty of War from your graveyard: Arm up to two target creatures you control. Activate only as a sorcery. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Tithe (When this creature enters, you may tap three other artifacts and/or creatures you control.)
When Cataclysmic Preacher's tithe is paid, return target instant or sorcery card from your graveyard to your hand.

Flying, haste
When Cataclysmic Skytyrant enters, sacrifice all other non-Dragon creatures you control. For each creature sacrificed this way, create a 3/3 red Dragon creature token with flying.

When Catacomb Dredger dies, return another target creature card from your graveyard to your hand.

Return target creature card from your graveyard to your hand. You may trigger a death knell of that card.

Catalina's Turf enters tapped.
When Catalina's Turf enters, you may mill two cards.
{T}: Add {B} or {R}.

You gain 5 life. Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Flashback {2}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Choose one. If you're horrific, you may choose both instead. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)
• Destroy target artifact.
• Catastrophic Crash deals 3 damage to target creature.

Creatures you control get +X/+X and gain trample until end of turn.

Return target tapped creature to its owner's hand. (Then exile this card. You may cast the creature later from exile.)

As an additional cost to cast this spell, discard two cards.
Draw three cards.

[+1]: Create a 1/1 red Human creature token with haste.
[–2]: Untap all creatures you control. Until end of turn, they gain “{T}: This creature deals 1 damage to each opponent.”
[–6]: You get an emblem with “Whenever a creature becomes tapped, this emblem deals 2 damage to any target and you gain 2 life.”

Whenever Cattish Bluestocking deals combat damage to a player, draw a card.
Attain {4}{U} ({4}{U}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Double strike

Renown 2 (When this creature deals combat damage to a player, if it isn't renowned, put two +1/+1 counters on it and it becomes renowned.)
Whenever Cauldish Arrogant becomes blocked by one or more creatures, reveal the top card of your library. Cauldish Arrogant deals damage equal to that card's mana value to each creature blocking it. Then put that card into your hand.

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
{1}{B}: You gain 1 life.

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
When Cauldish Cavalier becomes renowned, you may pay 2 life. If you do, draw two cards.

Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)

Bleed {1}{B}{B} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
All creatures get -4/-4 until end of turn.

First strike (This creature deals combat damage before creatures without first strike.)
Whenever Cauldish Warmonger attacks, create a 1/1 white Soldier creature token that's tapped and attacking.

Haste
Caulte Axeslinger gets +2/+2 as long as any opponent lost exactly 3 life this turn.

Other nonland permanents enter tapped.
Your opponents can't activate abilities of tapped permanents.

{1}{G}, Sacrifice Caustic Caterpillar: Destroy target artifact or enchantment.