msem-instigator

This spell can't be countered.
Flying, menace, haste
Ward—Sacrifice a creature. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player sacrifices a creature.)

{T}: Add {B} or {R}. You lose 1 life unless you have less life than an opponent.

This spell costs {2} less to cast if an opponent controls a creature with a bounty counter on it.
Postmark Bullet deals 3 damage to any target.

All creatures have “When this creature enters, destroy target creature with a lesser mana value.”

Whenever you cast a noncreature spell, Omegalomania deals 2 damage to any target. Whenever a permanent you don't control dealt damage this way dies this turn, return it to the battlefield tapped under your control.

Menace, haste
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.)

Flash (You may cast this spell any time you could cast an instant.)
When Gorillas in the Mist enters, prevent all combat damage that other creatures would deal this turn.

Each player sacrifices a creature. (Then exile this card. You may cast the artifact later from exile.)

Trample, vigilance
Spells your opponents cast that target Xiejuan and Hao Lu cost {X} more to cast, where X is the number of other creatures you control.
Whenever another creature you control dies, draw a card.

Enchant creature
You control enchanted creature.
At the beginning of your upkeep, enchanted creature's owner may have you draw three cards. If they do, sacrifice Take For Ransom.

Target creature you control gains erratic until end of turn. You may have it fight another target creature. (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)

Creatures you control gain double strike until end of turn. Whenever a creature you control deals combat damage this turn, put a +1/+1 counter on it.

Nonbasic lands have “Whenever this land becomes tapped, you lose 1 life unless you sacrifice this land.”

Put a +1/+1 counter on target creature. That creature gains flying until end of turn. Untap it.

This spell costs {1}{U} less to cast if it targets a red or green spell.
Counter target spell.
Draw a card.

Flying
Whenever a creature you control dies, each opponent loses life equal to its power.

Put a divinity counter on target creature. It gains “This creature has indestructible as long as it has divinity counter on it.” (This effect lasts indefinitely.)

When Primordial Gorran enters, if {B} was spent to cast it, put a +1/+1 counter on it for each creature card in your graveyard.

Young Dragonheart gets +1/+0 and has first strike as long as you control a legendary creature.

Destroy target creature or planeswalker. That permanent's controller loses 3 life unless that player sacrifices a nonland permanent or discards a card.

Double strike
Renown 2 (When this creature deals combat damage to a player, if it isn't renowned, put two +1/+1 counters on it and it becomes renowned.)

Exile target permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

(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.

When Landbirth Elemental enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Exile target creature or planeswalker, then for each counter on that permanent, you may put a counter of that kind on a permanent you control.