msem-instigator

Whenever another Zombie or Demon creature you control enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

When target creature you control dies this turn, return it or another creature card with an equal or lesser mana value from your graveyard to the battlefield tapped.

Haste
This creature can't block.
{2}{R}: Return this card from your graveyard to your hand.

When Corrupt Warden enters, up to one target creature gets -X/-X until end of turn, where X is the number of card types among cards in your graveyard.

This spell costs {1} less to cast for each card type among cards in your graveyard.
Deathtouch

Rhapsody {5}{R}{R} (Pay {5}{R}{R} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
When Corrupted Guardian enters, it deals damage equal to its power to up to one target player or planeswalker.

Invocation — When you spend four or more mana to cast a spell or activate an ability during your turn, transform Corrupted Sorcerer.

Enchant creature
Enchanted creature gets +3/-2.

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Corym's Elite can't be blocked by creatures with power 2 or less.

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.

Siphon (Each -1/-1 counter you put on your creatures up to their remaining toughness while casting this pays for {1}.)
Costly Ambush deals damage equal to the greatest power among creatures you control to target creature or planeswalker.

Purge, then you may tap an untapped creature you control. If you do, purge again. (To purge, exile two cards that share a type from graveyards. If you do, draw a card.)

Enchant creature
Enchanted creature gets +0/+1.
Enchanted creature deals combat damage equal to its toughness rather than its power.

Counter target spell.
Surveil 1.

Flash
Enchant creature
Enchanted creature gets +3/+3.

Flying
When Courier Eagle enters, target creature gets +2/+1 until end of turn.

{T}: Add {G}.
Concord — {T}: Add two mana in any combination of colors. Activate only if there are four or more card types among permanents you control.

As an additional cost to cast this spell, discard a card.
Draw two cards. The next card you foretell this turn costs {0} to foretell.

Target creature gets +3/+3 and gains trample until end of turn.
Reconstruct {3}{G} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

You mill two cards, draw two cards, lose 2 life, and create two Treasure tokens. (They're artifacts with “{T}: Sacrifice this permanent: Add one mana of any color.”)

This spell has flash as long as you control a permanent with flash.
Put target nonland permanent on top of its owner's library.

Wanderlust — This spell costs {2} less to cast as long as you control four or more differently named lands.
Crackle Across Kahembo deals X damage to target creature or planeswalker.

When Crackling Palm Ascetic enters, target creature gains double strike until end of turn.

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