msem-instigator

[+1]: Mill four cards, then return up to one creature card milled this way to your hand. You may activate a different loyalty ability Vivien has this turn.
[+1]: Create a 2/2 green Cat Spirit creature token with “When this creature dies, you gain 2 life.”
[–3]: Choose target creature you don't control. If it has flying, destroy it. Otherwise, up to one target creature you control deals damage equal to its power to that creature.
[–9]: Create four 4/4 green Hydra creature tokens. Creatures you control gain trample and haste until end of turn.

This spell costs {2} more to cast for each target beyond the first.
Choose one or more —
• Counter target activated or triggered ability from a nonland source.
• Vivien's Endeavor deals 6 damage to target attacking creature with flying.
• Target player searches their library for a creature card with colossal, reach, trample, or vigilance, reveals it, puts it into their hand, then shuffles.

When Volcano Elemental dies, it deals 2 damage to any target.

Colossal 3—{7}{G} (You may cast this for its colossal cost to have it enter with three +1/+1 counters; or pay {7}{G} as a sorcery: Put three +1/+1 counters on it if it has none.)
When Voracious Asvosydna's colossal ability puts one or more counters on it, you gain 5 life.

Flying
Whenever you attack with two or more creatures with flying, each opponent discards a card.

War-Pride Champion can't be blocked by creatures with power 2 or less.
Stampede — Whenever War-Pride Champion and a creature with greater power attack, target creature you control gets +2/+2 until end of turn.

Creature tokens you control have vigilance.
Whenever Watch of the Dead or another enchantment you control enters, create a 2/2 black Zombie creature token.

Waterfront Market enters tapped unless you control a basic land.
{T}: Add {W} or {U}.

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

Return target nonland permanent to its owner's hand. Scry 1.

Whispering Canal enters tapped unless you control a basic land.
{T}: Add {U} or {B}.

Colossal 4—{5}{G} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {5}{G} as a sorcery: Put four +1/+1 counters on it if it has none.)
Trample

Flash
Enchant creature
Enchanted creature gets +2/+2 and has flying and “At the beginning of your upkeep, you lose 1 life and create a 1/1 black Harpy creature token with flying.”

Double strike
The first spell you cast during each of your turns costs {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.

At the beginning of your upkeep, if there are three or more colors among creatures you control, you gain 2 life and draw a card.

Colossal 2—{4}{B}{B} (You may cast this for its colossal cost to have it enter with two +1/+1 counters; or pay {4}{B}{B} as a sorcery: Put two +1/+1 counters on it if it has none.)
Menace
When Wretched Catoblepas's colossal ability puts one or more counters on it, each opponent sacrifices a creature.

When Ziggurat Behemoth enters, target creature gets +3/+3 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Menace
When Zygos's Decimators enters, put a number of +1/+1 counters on it equal to your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Zygos, Underworld Scourge's power and toughness are each equal to the number of cards you own in exile and in your graveyard.
Spells you cast have “As an additional cost to cast this spell, you may exile any number of cards from your graveyard. This spell costs {1} less to cast for each card exiled this way.”