msem-instigator

When Benthic Shipcrasher enters, scry 3.

{1}, Exile Coiling Mystic from your graveyard: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Defender
Sacrifice two Islands: Deepsea Denizen loses defender until end of turn.

Colossal 4—{5}{U}{U}{U} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {5}{U}{U}{U} as a sorcery: Put four +1/+1 counters on it if it has none.)
Whenever Megalokraken enters or attacks, reveal the top X cards of your library, where X is Megalokraken's power. You may cast a noncreature spell with mana value X or less from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

This spell can't be countered.
{U}: Exile Skulkling. Return it to the battlefield under its owner's control at the beginning of the next end step.
{1}{U}: Until end of turn, Skulkling gets +1/-1 and can't be blocked.
{3}{U}: Draw a card. Create a 1/1 blue Rogue creature token.

Bloodprice {2}{U} (You may cast this card by sacrificing a creature and paying its bloodprice.)

Defender
Territorial Fangwurm may attack as though it didn't have defender as long as you've cast a cryptic spell this turn. (Artifacts, enchantments, and modal spells are cryptic.)

Once each turn, when a creature you control becomes tapped, you may untap that creature and tap up to one target creature.

When Titou Louoe, Bayou Shaman enters, create a blue Aura Curse enchantment token named Curse of Impotence attached to target player. The token has enchant player and “Creatures enchanted player controls get -1/-0.”

When Volaris Tideshaper enters, look at the top four cards of your library. Put one of those cards into your hand. and the rest on the bottom of your library in a random order.
Whenever you cast a noncreature spell, Volaris Tideshaper can't be blocked this turn.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

Flying
Cycling {2} ({2}, Discard this card: Draw a card.)

Civilized — Adorned Naga gets +2/+0 and has menace as long as you control an artifact, a creature, and an enchantment.

When CySec Spectre enters, you may sacrifice a creature. If you do, target opponent loses 3 life and you gain 3 life.

Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
At the beginning of your upkeep you lose life equal to the number of +1/+1 counters on Descendant of Caaseb.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Sacrifice another creature: Grotesque Defiler gains flying until end of turn.
Whenever Grotesque Defiler deals combat damage to a player, if you're in a renaissance, that player discards a card.

Indestructible
{2}{B}, Exile two cards from your graveyard: Each opponent loses 2 life and you gain 2 life.

Whenever a storied permanent you control enters, each opponent discards a card. (Enchantments and legendary permanents are storied.)

Flying
Other creatures get -1/-1.
Whenever Pan Long enters or deals combat damage to a player, return to the battlefield under your control target creature card from a graveyard that was put there from the battlefield this turn.

Indestructible
When Reflected Worldwalker enters, each player puts their hand into their sideboard.

When Scribal Puppeteer enters, create two 1/1 black Puppet creature tokens with “At the beginning of your upkeep, you lose 1 life.”

Flash
Wither (This deals damage to creatures in the form of -1/-1 counters.)

This spell costs {1} less to cast for each Zombie creature card in your graveyard.
When Undead Harbinger enters, return target Zombie card from your graveyard to your hand.