msem-instigator

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

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

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.

Equipped creature gets +2/+2.
Concord — Whenever equipped creature attacks, if there are four or more card types among permanents you control, create a 3/3 red Shark enchantment creature token that's tapped and attacking. Exile that token at the beginning of the next end step.
Equip {1}

[+1]: Create a tapped colorless artifact token named Conch Shell with “{T}: Add one mana of any color. Spend this mana only to cast permanent spells.”
[–1]: Reveal the top X cards of your library, where X is the number of card types among permanents you control. Put a permanent card from among them into your hand and the rest into your graveyard.
[–3]: Create two 3/3 red Shark enchantment creature tokens.

As Mysterious Cataract enters, you may pay 2 life. If you don't, Mysterious Cataract enters tapped.
{T}, Sacrifice Mysterious Cataract: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

{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.

Search your library for up to two cards with different names and reveal them. Target opponent chooses one of those cards. Put the chosen card into your graveyard and the rest into your hand. Then shuffle.

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.

I, II — Look at the top four cards of your library. You may reveal a permanent card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Discovery — At the beginning of your end step, you may put a permanent card from your hand onto the battlefield.

Stampede — Whenever Nacatl Skirmisher and a creature with greater power attack, creatures you control get +1/+0 until end of turn.
{R}, Sacrifice Nacatl Skirmisher: Destroy target artifact.

[+1]: Copy the next spell you cast this turn. You may choose new targets for the copy.
[–3]: Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.
[–8]: You get an emblem with “You may cast spells without paying their mana costs.”

Destroy target artifact or enchantment.
Scry 1.

This spell can't be countered.
Creatures you control have ward {2}. (Whenever one becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When Natural Philosopher enters, you gain 2 life for each creature you control with power 4 or greater.

{G}, Exile a creature card from your graveyard: Put two +1/+1 counters on target creature.

Destroy target artifact or enchantment.

Destroy target artifact or enchantment. Its controller gains 4 life.

Put a +1/+1 counter on target creature.
Flashback {1}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

As Nebula of Empty Gold enters, choose two or three colors. You lose life equal to the number of colors chosen this way.
{T}: Add one mana of any of the chosen colors.

Choose a creature card name. Each player sacrifices a creature, then each player who controls a creature with the chosen name gets a poison counter.
Draw a card.

Counter target noncreature spell.

Whenever Neon Claw Knight enters or attacks, choose one. Create a Function token with that effect. (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)
• This spell can't be countered.
• This spell costs {R} less to cast.
• If this spell would deal damage to a permanent or player, it deals that much damage plus 1 instead.