msem-instigator

Whenever Consuming Doom or another enchantment you control enters, you may have target creature get -1/-1 until end of turn.
Whenever a source an opponent controls destroys an enchantment you control, that player sacrifices a creature.

Consuming Flame deals 6 damage to target creature.
Ferocious — If you control a creature with power 4 or greater, the damage can't be prevented and that creature can't be regenerated this turn.

Destroy target land. Continental Collapse deals 2 damage to that land's controller.

Put target nonland permanent on top of its owner's library. If you control a Wizard, you may put that permanent on the bottom of its owner's library instead.

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.

Whenever Copse Crusher becomes blocked by one or more creatures, it gets +2/+2 until end of turn for each creature blocking it.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Cycling {U} ({U}, Discard this card: Draw a card.)

[+2]: Put two +1/+1 counters or loyalty counters on up to one other target creature or planeswalker.
[0]: Cornrose, the Mighty deals 3 damage to target creature. That creature deals damage equal to its power to Cornrose.
[–2]: Until end of turn, target creature gets +X/+X and gains trample, where X is its power.

When Zwurg enters, you may discard your hand. If you do, draw X cards and add X {R}, where X is the number of different sources that dealt damage to an opponent this turn.

Menace
Sacrifice another creature: Corpulent Gibberer deals 1 damage to any target.
Evoke {1}{R} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Exile a creature card from your graveyard: Put two loyalty counters on Corpus. Activate only as a sorcery and only once each turn.
[–2]: You may sacrifice a creature. If you do, create a 4/4 red Horror creature token with menace. Otherwise, create a 2/2 black Zombie creature token.
[–4]: Search your library for two non-Corpus cards and reveal them. Put one into your hand and the other into your graveyard, then shuffle.

Each player reveals the bottom six cards of their library. For each player, put up to one permanent card revealed this way onto the battlefield under your control.

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

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

Cosmic Catastrophe deals 6 damage to target creature or planeswalker. If you control a creature with power greater than its base power, Cosmic Catastrophe deals 3 damage to each opponent.

Destroy all creatures and planeswalkers. If five or more colors of mana were spent to cast Cosmic War, return a creature or planeswalker card from your graveyard to the battlefield.

When Cosmonaut Pioneer enters or leaves the battlefield, choose one—
• Scry 1, then draw a card.
• Create a 3/3 green Alien creature token with trample.
• You gain 5 life.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Flying
{2}{W}: Prevent all damage that would be dealt to and dealt by creatures with counters on them this turn.

When Cou Ling enters, create two 2/1 red and white Fox creature tokens.
Whenever a Fox you control deals combat damage to a player, draw a card, then you may cast an instant or sorcery card with mana value less than or equal to the damage dealt from your hand without paying its mana cost.

Reveal the top five cards of your library. For each card type, you may put a card of that type revealed this way into your hand. Put the rest into your graveyard. Then you may cast a nonland card with mana value 3 or less from your hand without paying its mana cost.

For each creature you control, create a token that's a copy of it. They gain haste. Sacrifice them at the beginning of the next end step.

When Crane-Style Ascetic enters, choose one —
• Create a 1/1 white Bird creature token with flying.
• Put a +1/+1 counter on target creature you control.

Crater Burst deals 3 damage to any target. Add {W}{U}{B}{R}{G}. Until end of turn, you don't lose this mana as steps and phases end.

Trample
Whenever Crazed Wildlings deals combat damage to a player, create a 1/1 red Goblin creature token.