msem-instigator

Multipurpose Mannequin gets +1/+1 for each permanent attached to it.

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.

As an additional cost to cast this spell, pay {2} or put a -1/-1 counter on a creature you control.
Munitions Explosion deals 3 damage to any target.

Destroy target creature.

Whenever a creature with flying attacks you, gain control of that creature at end of combat.

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

Destroy target creature an opponent controls, then that player sacrifices a creature.

Whenever Murkriver Trawler attacks, until end of turn, target Rogue gains “Whenever this creature deals combat damage to a player, draw a card.”

Murky Path enters tapped unless you control one or fewer other lands.
{T}: Add {U} or {B}.
Cycling {2} ({2}, Discard this card: Draw a card.)

{T}, Pay 1 life: Add {B}.
{T}, Pay 1 life, Sacrifice Murky Peat: Search your library for a Swamp card, put it onto the battlefield tapped, then shuffle.

({T}: Add {U} or {B}.)
Whenever Murmuring Falls becomes tapped, you lose 1 life unless you control two or more basic lands.

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.)

Draw two cards.
Crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase. For each planeswalker you control, you may activate its loyalty abilities an additional time this turn.

({T}: Add {G} or {U}.)
As Mushroom Lagoon enters, you may pay {1}. If you don't, Mushroom Lagoon enters tapped.

At the beginning of your upkeep, germinate. Then if creatures you control have total power 10 or greater, transform Mushroom Merchant. (To 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.)

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

{T}: Add {C}.
Whenever Mustering Grounds becomes tapped, if it's enchanted, you may pay {2}. If you do, create a 1/1 white Soldier creature token with vigilance.

You may have Mutalithic Golem enter as a copy of any land on the battlefield, except it's an artifact in addition to its other types.

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

Whenever a creature you control dies, destroy target creature you don't control.