msem-instigator

Glitch—Discard a card. (Remove one [restriction] for each time you pay the glitch cost.)
Add {R} for each [Mountain] land you control, then exile the top three cards of your library. You may play [one of] those cards this turn.

Maniac Macaque attacks each combat if able.
Whenever Maniac Macaque becomes blocked by a creature, Maniac Macaque deals 1 damage to that creature.

Menace
Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)

{T}: Discard two cards. If you do, draw two cards.

Add {R} and two mana of any one color.
When you next cast a spell this turn, Manifest Irrationality deals 3 damage to any target.

First strike
Manifold Manipulator has lifelink as long as you control a white permanent. The same is true for flying and blue, menace and black, and trample and green.

When Marauding Goliath becomes blocked by a creature with power 1 or less, sacrifice it at end of combat.

Target creature's controller judges it. Then if they honored it, you gain control of that creature until end of turn. Untap it. It gains haste until end of turn. (That creature's controller honors it by putting a +1/+1 counter on it or condemns it by sacrificing it to draw a card.)

[+1]: Discard a card. If you did, draw a card.
[–2]: Create a Bullet token. Until end of turn, if a Bullet you control would deal damage, it deals that much damage plus 1 instead. (It’s an artifact with “{T}, Sacrifice this artifact: It deals 1 damage to any target.”)

Whenever Maritime Thug becomes tapped, it deals 1 damage to each opponent.

Gain control of target creature until end of turn. Put a +1/+1 counter on it and untap it. That creature gains haste until end of turn.

As an additional cost to cast this spell, discard a card or sacrifice an artifact.
Draw two cards and create two Treasure tokens. (They're artifacts with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Menace (This creature can't be blocked except by two or more creatures.)

Menace (This creature can't be blocked except by two or more creatures.)
Whenever a nontoken creature you control dies, exile the top card of your library. You may play that card until the beginning of your next end step.

First strike
Whenever Martial Maestro attacks, other attacking creatures you control get +1/+0 until end of turn.

Target creature gets +1/+1 until end of turn. Then draw a card if that creature is a Warrior.

Flying, double strike
Whenever Marzela Falkenrath deals combat damage to a player, create a 1/1 black and red Vampire creature token with menace.
{2}{B}: Vampires you control gain lifelink until end of turn.

Discard your hand, then draw two cards for each land card discarded this way. For each opponent, Marzen's Frenzy deals damage to that player or a planeswalker they control equal to twice the number of instant or sorcery cards discarded this way.

As an additional cost to cast this spell, discard a card at random.
Draw three cards.

Sacrifice Masahita's Servant: Exile the top card of your library. Until end of turn, you may play that card.

At the beginning of your upkeep, exile the top card of your library. Masahita, Bloodtongue deals damage to you equal to that card's mana value. Until end of turn, you may play that card.

First strike
When Masha Ritualist enters or whenever you cast a spell, if {B}{G} was spent to cast it, return target creature card with mana value 3 or less from a graveyard to the battlefield under your control. Put a +1/+1 counter on Masha Ritualist.

Whenever Masha's Vanguard deals damage to a player, you may put a creature card with mana value X or less from your hand onto the battlefield, where X is the amount of damage dealt this way.

Creatures your opponents control attack each turn if able.
Blocking creatures you control get +4/+0.
{W}: Untap Masha, Hero of Pelastrov.

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Masked Lancer has first strike as long as it's attacking.
Whenever Masked Lancer mentors a creature, that creature gains first strike until end of turn.