msem-instigator

Choose target creature. Scry 3, then reveal the top card of your library. You gain X life and put X +1/+1 counters on that creature, where X is the revealed card's mana value.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, each opponent loses life equal to Morose Harpist's power.

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.

Mossvine Lurker has trample as long as it has a +1/+1 counter on it.

({T}: Add {B} or {G}.)
Mossy Shrine enters tapped unless you control two or more basic lands.

Flying
Whenever another creature you control enters, you gain 1 life.

Flying
When Mother of Owls dies, you may return target creature an opponent controls to its owner's hand.

Creatures you control get +2/+2 and gain first strike until end of turn.

First strike, haste
When Mounted Marksman enters, it deals 2 damage to target creature you don't control.

Scry 2, then reveal the top or bottom card of your library. Creatures you control get +X/+X until end of turn, where X is that card's mana value.
Draw a card.

When Mul Daya Elder enters, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Whenever a land you control enters, put a +1/+1 counter on Mul Daya Elder.

Exile a nonland card from your graveyard: For each colored mana symbol in that card's mana cost, add one mana of that color. Activate only once each turn. (For example, if the card's mana cost is {3}{G}{G}{W}, you add {G}{G}{W}.)

When Mulchborn Behemoth enters, you may sacrifice any number of lands.
Mulchborn Behemoth gets +1/+1 for each land card in your graveyard.
{B}{G}, Sacrifice a land: Destroy target creature or land.

Look at the top three cards of your library, then put them into your graveyard or back on top of your library in any order.
Draw two cards.

As an additional cost to cast this spell, exile a creature card from your graveyard.
Create a tapped 2/3 black Mummy creature token.

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

Create two 1/1 white Soldier creature tokens. Prevent all damage that would be dealt to them this turn.

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

Each player mills three cards. For each instant and/or sorcery card milled this way, draw a card.

[+1]: Reveal the top card of your library and put that card into your hand. You lose life equal to its mana value.
[0]: You gain 1 life for each card in your hand.
[–7]: Search your library for up to X cards, where X is the number of cards in your hand, and put them into your hand. Then shuffle.

You draw X cards and you lose X life, where X is the number of cards in your graveyard.

When Naiad of the Glen enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Naiad of the Glen has trample as long as it has a +1/+1 counter on it.

Trial 2 (As you cast this spell, an opponent of your choice may pay 2 life. If they don't, they fail the trial.)
When Nascent Adversary enters, if the trial was failed, it gains haste and first strike until end of turn.

Defender (This creature can't attack.)
When Naturebound Druid enters, you may search your library for a basic land card, reveal it, then shuffle and put that card on top.

Target creature gains deathtouch until end of turn. Regenerate it.