msem-instigator

({T}: Add {B}.)
As Stygian Dunes enters, you may pay 1 life. If you don't, Stygian Dunes enters tapped.

When Stygian Leviathan enters, target opponent loses life equal to the number of Curses attached to them and you gain that much life.

Destroy target untapped creature.

Tap up to two target creatures. Those creatures don't untap during their controllers' next untap steps. Scry 1.

Trample, haste
Whenever Sugon, Destruction's Fist deals combat damage to a player, return it to its owner's hand unless you have Sugon deal 5 damage to you.

When Suitor of the Glade enters, put two +1/+1 counters on target creature you control. It gains vigilance until end of turn.

At the beginning of your upkeep, Suitor of the Sea deals 1 damage to each player.

When Sullen Bonecrusher enters, it deals damage to any target equal to the number of Warriors you control and you gain that much life.

Menace
At the beginning of your upkeep, you may pay 3 life. If you do, draw a card.

Enchant creature
Enchanted creature has base power and toughness 3/3.

You may have Sun Yun enter as a copy of any creature on the battlefield, except her name is Sun Yun, Master of Man, she's legendary in addition to her other types, and she has “{2}{U}: Exile Sun Yun, then return her to the battlefield under her owner's control.”

If a creature entering the battlefield under your control causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
{1}{U}, {T}: Exile another target creature. Return it to the battlefield under its owner's control at the beginning of the next end step.

{2}: Other creatures you control get +1/+0 until end of turn.
Whenever Sun-Crowned Flagship attacks, each attacking creature you control gains trample until end of turn.
Crew 7 (Tap any number of creatures you control with total power 7 or greater: This Vehicle becomes an artifact creature until end of turn.)

You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost.

As Sunless Ridge enters, you may tap an untapped creature you control. If you don't, Sunless Ridge enters tapped.
{T}: Add {B} or {R}.

Sunrazed Ruins enters tapped.
{T}: Add {W}.
{2/W}{2/W}: Sunrazed Ruins becomes a 2/3 white Elemental creature with lifelink until end of turn. It's still a land.

Sunspear Surge deals 2 damage to target creature and 1 damage to each other creature.

{T}, Pay 1 life: Add {R}.
{T}, Pay 1 life, Sacrifice Sunwashed Spires: Search your library for a Mountain card, put it onto the battlefield tapped, then shuffle.

Enchant creature
Enchanted creature gets +3/+3, has trample, and can only attack alone.

When Suraj Militant enters, target creature gets +1/+1 until end of turn.

{2/R}: Suraj Outrider gets +1/+0 until end of turn.

Submerge up to two target attacking nontoken creatures an opponent controls. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

As an additional cost to cast this spell, discard a card.
Return up to one target instant card and up to one target sorcery card from your graveyard to your hand. Exile Sustaining Meditation.

At the beginning of your end step, put a flood counter on Swelling Sea, then return each nonland permanent with mana value less than or equal to the number of flood counters on Swelling Sea to its owner's hand.