msem-instigator

{3}, Sacrifice Titanic Fossil: Mill three cards, then you may exile a card from your graveyard. You may cast a copy of the exiled card without paying its mana cost if the spell's mana value is 3 or less. Activate only as a sorcery.
{3}{U}{B}: Return Titanic Fossil from your graveyard to the battlefield transformed. Activate only during your turn.

Return target permanent you control to its owner's hand. (Then exile this card. You may cast the creature later from exile.)

Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)
When Tomb Steward enters, search your library for a card and put it into your graveyard. Then shuffle.

Ward {2}
Even numbered spells you cast each turn costs {2} less to cast. (The second, fourth, sixth, etc.)

Whenever Toxic Miscreant deals combat damage to a player, that player discards a card.

Search your library for a creature card, reveal it, then shuffle and put that card second from the top.

Draw a card. (Cast a copy of this spell once while this creature is on the battlefield.)

Deathtouch

(Transform this if it's not attached to a creature. Pay {2}{W} as a sorcery to unattach it.)
Enchant creature you control
Trusty Steed's rider gets +2/+2.

Hexproof
Whenever this creature transforms into Tsunami Titan or attacks, you may return target creature to its owner's hand.

Double strike
Ride {2}{W} ({2}{W}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Target player loses 3 life and you gain 3 life. (Then exile this card. You may cast the creature later from exile.)

Menace
Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)

Sacrifice a creature: Two-Faced Aristocrat gains indestructible until end of turn.
Attain {4}{B} ({4}{B}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Trample, haste
When Tyrants of Bundan enters, tap all lands target player controls. They don't untap during their controller's next untap step.

Target creature gets -5/-0 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Unbound Spirit can't be blocked.
When you attain Unbound Spirit, tap target creature. That creature doesn't untap during its controller's next untap step.

Flying, vigilance
When you attain Unfallen Angel, target opponent discards a card.

Unfettered Noble can't be blocked unless defending player pays 3 life, discards a card, or sacrifices a nonland permanent for each creature they control that's blocking it.
Sacrifice a nonland permanent: Unfettered Noble gains indestructible until end of turn.

Ungoverned Sneak can't be blocked by creatures with greater power.
Attain {3}{U} ({3}{U}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Until end of turn, you can't lose the game, your opponents can't win the game, and your life total can't change.

Other creatures you control get +1/+0.
At the beginning of combat on your turn, create a 1/1 red Human creature token with haste.

Menace
Unveil {3}{B}{R} ({3}{B}{R}: Transform this. Unveil only as a sorcery.)

Unvirtuous Maestro can't be blocked except by three or more creatures.

Disgraced 1 (This enters with a -1/-1 counter. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)
Attain {3}{W} ({3}{W}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)