msem-instigator

Braineater Abominus can't be blocked by creatures with power 4 or greater.
Whenever a creature you control deals combat damage to a player, exile the top card of that player's library. You may play that card for as long as it remains exiled, and you may spend mana as though it were mana of any type to cast it.

Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, Brine Cultist can't be blocked this turn.
{5}{U}: Draw a card.

Flying
When Carrion Drake enters, you may exile a creature card from your graveyard. If you do, draw a card.

Return up to one target nonland permanent you control and up to one target nonland permanent you don't control to their owners' hands.
Flashback {4}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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

Whenever Conjured Stalker attacks, you may draw a card. If you do, discard a card.

Flash
Enchant player
When Curse of Doubt enters, counter target spell enchanted player controls unless they pay {2}.
{4}{U}: Enchanted player mills three cards.

Enchant player
When Curse of Scuttling Thoughts enters, create a 0/3 blue Crab creature token with “{T}: Target player mills a card.”
If enchanted player would mill one or more cards, they mill twice that many cards instead.

Enchant player
When Curse of the Breathless enters, create a 1/1 white Spirit creature token with flying for each Curse attached to enchanted player.
Whenever another Curse becomes attached to enchanted player, create a 1/1 white Spirit creature token with flying.

Enchant player
Whenever Curse of the Tattletale or another Curse becomes attached to enchanted player, each of their opponents draws a card.

Enchant player
Whenever enchanted player casts a spell from anywhere other than exile, exile that spell. During that player's next turn, they may cast that card without paying its mana cost.

Defender
When Drunau Egg enters, target player mills two cards.
{3}{U}{U}: Transform Drunau Egg. Activate only as a sorcery and only if an opponent has thirteen or more cards in their graveyard.

Trample

Whenever Ensnaring Possessor attacks, you may tap or untap target permanent.
{1}{U}, {T}: Until end of turn, target creature gets +1/+1 and gains “Whenever this creature attacks, you may tap or untap target permanent.” Activate only as a sorcery.

Enchant creature
When Erase Identity enters, tap enchanted creature.
Enchanted creature loses all abilities.
Enchanted creature doesn't untap during its controller's untap step.

When Escaped Ooze enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
{3}{G}: Put a +1/+1 counter on Escaped Ooze.

You may shuffle your graveyard into your library. Draw X cards.
Flashback {X}{U}{U}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Vigilance
{T}: Target instant or sorcery card in your graveyard with mana value 3 or less gains flashback {0} until end of turn. Activate only as a sorcery. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

When Geistmage's Grimoire enters, draw two cards.
{4}{U}, {T}: Target creature can't be blocked this turn.

Put a +1/+1 counter on target creature you control. It can't be blocked this turn.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Flying
Whenever Havengul Banshee attacks, each creature defending player controls gets -1/-0 until end of turn.
{3}{U}: Return Havengul Banshee from your graveyard to the battlefield transformed under your control attached to target opponent. Activate only as a sorcery.

Enchant player
Creatures enchanted player controls get -1/-0.
If Curse of the Banshee would be put into a graveyard from the battlefield, exile it instead.

Flying
When Krothuss, Abyssal Terror dies, return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.
Foreshadow {6}{U}{U} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

Vigilance
{2}, {T}: Target player mills two cards.

Other Spirits you control get +1/+1.
Whenever Mistmourner or another Spirit you control enters, you may draw a card. If you do, discard a card.