msem-instigator

Converge — Counter target spell unless its controller pays {1} for each color of mana spent to cast Cosmic Sinkhole.

Pressure—{B}, Pay 5 life. (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Create an X/X black Horror creature token, where X is the number of cards in your graveyard.

Pressure—{4}{U}{B}, Sacrifice two creatures. (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Whenever Oryxyth enters or attacks, create an X/X black Horror creature token, where X is the number of cards in your graveyard.
{U}{B}, Sacrifice another creature: Gain control of target creature with power less than the sacrificed creature's power.

Choose target card in a graveyard other than a basic land card. Search its owner's graveyard, hand, and library for any number of cards with the same name as that card and exile them. Then that player shuffles.
Scry 1.

Destroy target creature with power or toughness 2 or less.

Whenever Wakeborne Kraken or another Kraken, Leviathan, Octopus, or Serpent you control enters, you may return target creature an opponent controls to its owner's hand.
Whenever a creature an opponent controls leaves the battlefield, if it didn't die, draw a card.