msem-instigator

Menace
When this creature enters, put a -1/-1 counter on a creature you control.

Flash
Flying
Whenever you cast a spell during an opponent's turn, create a Weapon token. When you do, you may attach it to another target creature with flying. (It's an Equipment artifact token with equip {2} and “Equipped creature gets +1/+1”.)

Flying
When Skymount Reinforcements enters, put a +1/+1 counter on another target creature.

Flying
When Skystream Mantas is returned to your hand from the battlefield, draw two cards.

Flying
When this creature enters, target creature gains flying until end of turn.
Arise {3}{W}{W} ({3}{W}{W}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

Rhapsody {3}{W}{W} (Pay {3}{W}{W} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Players can't search libraries unless they pay {X}, where X is Skytouch Distorter's power.

Flying
At the beginning of your upkeep, sacrifice Skyward Dreamers unless you remove a counter from a permanent you control.

Improve {1}{B/R} ({1}{B/R}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
At the beginning of each player's combat, you may have that player create two goaded 1/1 red Goblin creature tokens with haste. Exile those tokens at end of combat. (Until your next turn, they attack each combat if able and attack a player other than you if able.)

Deathtouch, menace
Slayer of the Famed must be blocked each combat if able.

Ward {2}
Slippery Bunyip can't be blocked except by creatures with Adventures.

Slippery Capuchin can't be blocked.
Whenever Slippery Capuchin becomes the target of a spell or ability, you may change the target of that spell or ability.

{1}{R}: Target creature can't block Slippery Salamander this turn.

Whenever you cast an instant, sorcery, or Wizard spell, Slipsand Runemage deals 1 damage to any target.

As long as there are four or more card types among cards in your graveyard, Slipstream Silencer can't be blocked.
Whenever Slipstream Silencer attacks, surveil 1.

Whenever Slithering Eyes deals damage to a player, you may exile that many cards from the top of your library. Until the end of your next turn, you may play those cards.

Advance {5}{B}{B} (Cast this for {5}{B}{B} to advance it as it enters. {5}{B}{B}: Advance this as a sorcery.)
Whenever Sluiceway Collector advances, put a permanent card from a graveyard onto the battlefield under your control.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
{2}{B}, Sacrifice Sluiceway Shrieker: Put the bottom card of your library into your hand.

When Slyten Analyst enters, you may search your library for a card, then shuffle and put that card on top. If you do, you lose 2 life.

Flying
{R}: Slyten Ignitor gets +1/+0 until end of turn.

When Smokeweaver Initiate dies, draw a card.

Whenever you discard an instant or sorcery card, you may cast it from your graveyard. (You still pay its costs.)
Spells you cast from anywhere other than your hand cost {1} less to cast.

Prowess
When Snowline Ascetic enters, you may put target instant or sorcery card from your graveyard on top of your library.

When Sofia's Swashbucklers enters, you may return target card with foretell from your graveyard to your hand.

Solar Hatching deals 4 damage to each creature.
Coalesce {6}{R}{R} (You may cast this from your graveyard for {6}{R}{R}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
When Solar Hatching enters, each player chooses up to two lands they control and sacrifices the rest.

First strike