msem-instigator

{T}: Add {C}.
{6}, {T}, Discard a card: Search your library for a multicolored card, exile it, then shuffle. If its mana value is 3 or less, you may cast it without paying its mana cost. If you don't, put it into your hand. Activate only as a sorcery.

Rhapsody {5}{W}{W} (Pay {5}{W}{W} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Whenever Oltenen Paradise-Seeker attacks, up to one target creature's base power and toughness each become equal to Oltenen Paradise-Seeker's power and toughness until end of turn.

Reach
When Oltenen Terror enters, crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)
{1}{G}, Sacrifice an artifact or creature: Tap Oltenen Terror. It gains indestructible until end of turn.

Whenever you cast a noncreature spell, Omegalomania deals 2 damage to any target. Whenever a permanent you don't control dealt damage this way dies this turn, return it to the battlefield tapped under your control.

{3}{U}, Exile a card from your graveyard: Omen Serpent can't be blocked this turn.

Target creature gets -5/-5 until end of turn. Scry 1.

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

Play with the top card of your library revealed.
Whenever you draw a card, destroy each creature with the same mana value as that card.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Spells you cast from zones other than your hand cost {3} less to cast.

Flying
Whenever Omid enters or one or more Armies you control attack, recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Ominous Dragoncaller gets +1/+1 and has flying as long as you control a Dragon.

Equipped creature gets +0/+3 and has menace. (It can't be blocked except by two or more creatures.)
Equip {1}

Ominous Lair enters tapped unless you have 15 or less life.
{T}: Add {W} or {B}.

Ominous Lightning deals 3 damage to target creature. Scry 2.

{T}: Add {U} or {B}. You lose 1 life unless you have less life than an opponent.

When Ominous Presence enters, search your library for a Curse card, reveal it, then shuffle. If it has mana value 4 or less, you may put it onto the battlefield. Otherwise, put it into your hand.
Ominous Presence gets +1/+1 for each Curse attached to your opponents.

Ominous Quag enters tapped.
{T}: Add {W} or {B}.
{2}{W}{B}, {T}, Sacrifice Ominous Quag: Draw a card.

Whenever you draw a card, put a foreshadow counter on Ominous Seas.
Remove eight foreshadow counters from Ominous Seas: Create an 8/8 blue Kraken creature token.
Cycling {2} ({2}, Discard this card: Draw a card.)

Target creature gets -2/-2 until end of turn.
{3}{B}{B}, Exile Ominous Wind from your graveyard: Each creature gets -2/-2 until end of turn. Activate only as a sorcery.

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.

Post a bounty on target creature you don't control, then each opponent sacrifices a creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

I, II — Put your choice of a flying or hexproof counter on target creature you control.
III — Creatures you control with counters on them can't be blocked this turn unless defending player pays {3} and spells that target those creatures cost an additional {3} to cast until your next turn.
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Exile target creature or enchantment you control, then return that card to the battlefield under your control.
You may cast On Repeat from your graveyard any time you could cast a sorcery by discarding a land card in addition to paying its other costs.

Proliferate (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)
Scry 2, then draw a card.

Whenever a creature dies, put a +1/+1 counter on each creature you control with power less than it.
{3}{G}, Sacrifice a creature: Draw cards equal to the sacrificed creature's power.