msem-instigator

Morningstar Blaze deals X damage divided as you choose among one or two targets.

Choose up to one target land card and up to one target creature card with mana value 3 or less from your graveyard. Return one to the battlefield and the rest to your hand.

Target creature gets -2/-2 until end of turn. Mill two cards.

Players can't gain life.
At the beginning of each player's upkeep, if that player has 10 or less life, they lose 1 life.

Motley Crew has no name while it's being cast. (It will always make first contact.)
{2}{R}: Creatures you control named Motley Crew get +1/+0 until end of turn.

{4}{G}: Monstrosity 2. (If this creature isn't monstrous, put two +1/+1 counters on it and it becomes monstrous.)
When Mountain Bighorn becomes monstrous, you may have it fight target creature you don't control.

When Mountain-Western Inventor enters, you may return target artifact card from your graveyard to your hand.
{1}, Sacrifice an artifact: Target creature can't block or be blocked this turn.

Return target nonland permanent card with mana value 2 or less from your graveyard to the battlefield.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Vanishing 3 (This permanent enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a creature dies or a time counter is removed from Mourn the Lost, you may tap target creature.

Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

When Mouthpiece of Yhzag enters, you may have target opponent create a tapped 1/1 colorless Human creature token.
Whenever Mouthpiece of Yhzag attacks, gain control of target Human creature you don't control with mana value 3 or less until end of turn. Tap it. It's attacking.

Whenever Mukal Sire or another Construct you control enters, Mukal Sire deals 1 damage to each opponent.
Respawn (When this creature dies, if it attacked this turn, return it to its owner's hand.)

Respawn (When this creature dies, if it attacked this turn, return it to its owner's hand.)

Destroy target planeswalker. Mummy's Grin deals 2 damage to that planeswalker's controller.

Enchant creature
Whenever enchanted creature attacks, it gets +3/+3 and gains trample until end of turn.

Return target creature to its owner's hand. You may shuffle up to four target cards from your graveyard into your library.

Target creature gets -1/-1 until end of turn. Germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Counter target enchantment, instant, or sorcery spell. (Then exile this card. You may cast the creature later from exile.)

Put a +1/+1 counter on up to one target creature. (Then exile this card. You may play the land later from exile.)

First strike
When Mutilated Warrior enters, you may have it deal damage to each player equal to the number of Warriors you control.

Whenever Mysteries of Life enters or you create a token, choose one that hasn't been chosen this turn —
• You gain 2 life.
• Draw a card, then discard a card.
• You may tap or untap target permanent.

{X}, Exile Mysterious Coffer: Return all nonland permanents with mana value X or less to their owner's hands.

(As you complete a condition, decode it. After all are decoded, you solve the mystery and transform this.)
When Mystery of the Crashed Craft enters, create two 1/1 red Alien creature tokens with “This creature can't block.”
{MG}—You cast an instant spell.
{MG}—You cast a sorcery spell.

Whenever you cast a spell from exile, you may draw a card.
At the beginning of your upkeep, you may reveal the top card of your library.

When Mystic Seer enters, each player may scry 1.
{2}{U}: Draw a card, then discard a card.