msem-instigator

I, II — Whenever a creature you control attacks alone this turn, put a +1/+1 counter on it.
III — Whenever a creature you control attacks alone this turn, it gains double strike and lifelink until end of turn.

Shadow Ball deals 2 damage to target creature or planeswalker and 2 damage to its controller. You gain 2 life.

Shadow Courier can't be blocked.

Your opponents play with their hands revealed.

(Activate each submodule once as a sorcery. When this enters, activate one submodule for free.)
{2}{U}: Imitate
Choose any number of target cards in graveyards. Their owners shuffle them into their libraries. Then you draw a card.
{2}{B}: Deceive
Surveil 5.
{1}{U}{B}: Obfuscate
Shadow Module gains “At the beginning of your upkeep, if there are four or more card types among cards in your graveyard, you may draw a card.”

All creatures get -3/-3 until end of turn.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, if a creature would die this turn, exile it instead.

Flash
When Shadow Stalker enters, for each player, look at the top card of that player's library. You may have that player put that card into their graveyard.

When Shadow of Izumito dies, choose one —
• Destroy target creature that was dealt damage this turn.
• You may put a progress counter on a Project you control.

Shadowcleft Hideout enters tapped.
{T}: Add {B}.
{T}, Pay 2 life, Sacrifice Shadowcleft Hideout: Draw a card.

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Reach (This creature can block creatures with flying.)
If Shadowcreep was kicked, it enters with two +1/+1 counters on it.

When Shadowlurk enters, if a creature died this turn, put a +1/+1 counter on it.

When Shadowstrider dies, create a 2/2 colorless Spirit creature token.

Draw two cards. You lose 2 life. Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Discard your hand. Draw cards equal to the number of creatures that died this turn.

Prowess
Each instant and sorcery card with mana value 3 or less in your hand has inscribe. The inscribe cost is equal to its mana cost increased by {1}{U/R}. (Pay that card's mana cost increased by {1}{U/R}: Exile that card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Enchant creature
You control enchanted creature.
When Shahmaran's Captivation enters, untap enchanted creature. It gains haste until end of turn.

When Shaidostan Cryoforger enters, exile the top card of your library.
When Shaidostan Cryoforger dies, you may put the exiled card into your hand.

[+1]: Up to two target creatures you control each get +1/+0 and gain first strike until end of turn.
[0]: You may sacrifice a creature. If you do, Shala Na, Urshadi Apostate deals 3 damage to any target.
[–3]: Discard your hand, then draw three cards.

Shala's Immolation deals 5 damage to target creature and 2 damage to that creature's controller.

Haste
Whenever Shala's Phantasm attacks, you may sacrifice a creature. If you do, Shala's Phantasm deals 3 damage to any target.

When Shaman of Burning Ashes enters, return target instant or sorcery card from your graveyard to your hand. When you do, each opponent loses X life, where X is that card's mana value.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
When Shaman of the First Pact enters, exile up to four target creature cards from graveyards. You may cast them for as long as they remain exiled and you may spend mana as though it were mana of any type to cast them.

When Shambling Gutless enters, target player discards a card.

Shambling Hive power and toughness are each equal to the number of Insects you control.
Shambling Hive has vigilance as long as you control four or more Insects, and has trample as long as you control eight or more Insects.

Trample
While you're searching your library, if Shambling Manglers dealt combat damage to an opponent this turn, you may play lands from your library.