msem-instigator

Hexproof
Whenever another creature you control becomes the target of a spell an opponent controls, you may submerge that creature. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)
{1}{U}{U}: Turn target face-down creature you control face up.

Target creature gets -2/-2 until end of turn.
Dominance — That creature gets -4/-4 until end of turn instead if you control the creature with the greatest power or tied for the greatest power.

For each counter on each permanent you control, you may put another counter of that kind on that permanent.
Draw a card.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
When the fourth spell of a turn is cast, you may unlock Mirror Cipher. If the revealed card is an instant or sorcery card, cast it without paying its mana cost and copy it. You may choose new targets for the copy.

First strike
Mauling Mother gets +1/+1 for each other creature you control.

Counter target artifact or sorcery spell.

Enchant player
Whenever one or more creatures you control die, enchanted player loses 1 life and you gain 1 life.

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 Soul Trapper enters, tap target creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Soul Trapper.

Flying
When Hallowed Perspective enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
You may exert Hallowed Perspective as it attacks. When you do, until your next turn, you may cast spells as though they had flash. (An exerted creature won't untap during your next untap step.)

When Rootwarper enters, you may sacrifice a land. If you do, search your library for a land card, put that card onto the battlefield tapped, then shuffle.

When Curator of Cures enters, adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)
Whenever an Aura you control enters, you gain 1 life.

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

Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)
Hopeless Wanderer can't be blocked.

Haste (This creature can attack and {T} as soon as it comes under your control.)
Double strike (This creature deals both first-strike and regular combat damage.)

You may put a creature or Revelation card from your hand onto the battlefield. Exile that permanent if it would leave the battlefield. If it's a Revelation, it enters as a Horror creature.
Coalesce {7}{U}{U} (You may cast this from your graveyard for {7}{U}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Instant and sorcery spells you control have leitmotif. (Exile that spell as it resolves if you cast it from your hand. When you next cast a spell that shares a color with that card, you may cast it from exile without paying its mana cost.)

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a creature card that shares a creature type with the sacrificed creature with mana value less than or equal to X plus the sacrificed creature's mana value, put it onto the battlefield, then shuffle.

Menace
Whenever Entrail Elemental deals combat damage to a player, you may cast target card from your graveyard this turn. If an instant or sorcery spell cast this way would be put into your graveyard, exile it instead. (You still pay its costs. Timing rules still apply.)

First strike
Redeye Commando's power is equal to twice the number of artifacts you control.
Redeye Commando attacks each turn if able.
Whenever Redeye Commando attacks, if its power is 6 or greater, it gains menace and trample until end of turn.

Voracious 2 (As this enters, you may sacrifice up to two artifacts and/or creatures. This creature enters with that many +1/+1 counters on it.)
Trample
At the beginning of your end step, if a creature died under your control this turn, create a 1/1 green Saproling creature token.

Whenever Brine Kelpie attacks, you may tap target creature an opponent controls.
Ride {2}{U} ({2}{U}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Flash
Haste
{3}, {T}: Exchange control of two target noncreature spells. Their controllers may choose new targets for the spells.

Choose two or four —
• Exile target player's graveyard.
• You gain 4 life.
• Create a 2/2 white Knight creature token with vigilance.
• Conjure a card named Fatigue and put it on top of your library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

Destroy target creature or planeswalker. Create a tapped colorless land token named Fading Rift with “{T}, Sacrifice this land: Add one mana of any color.”

For any number of target spells or abilities your opponents control, counter it unless its controller pays {4}.