msem-instigator

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 permanents 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 the battlefield, target creature gets +3/+3 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Menace
When Zygos's Decimators enters the battlefield, 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.”