msem-instigator

You may have Unstable Impersonator enter as a copy of any creature on the battlefield chosen at random.

Vanishing 5 (This creature enters with five time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
{1}{R}, Remove a time counter from Unstable Magmaling: Flip a coin. If you win the flip, it deals 3 damage to any target.

Return target creature card from your graveyard to the battlefield with an additional -1/-1 counter on it.

Unstoppable Slaughter deals 1 damage to each creature and each player. Whenever a creature dealt damage by Unstoppable Slaughter this turn dies this turn, repeat that process.

Choose one, then choose another for each card named Unsuspecting in your graveyard.
• You may return a permanent you control to its owner's hand.
• You may put an artifact, creature, or land card with mana value 2 or less from your hand onto the battlefield.
• Untap up to three target permanents.
• You gain 4 life.

Whenever a land becomes tapped, its controller sacrifices it and creates a Treasure token.

Whenever you cast a nongreen spell, creatures you control get +1/+1 until end of turn.
Wanderlust — When Untethered Disciple enters, if you control four or more differently named lands, create two 1/1 Scout creature tokens that are all colors.

{T}: Add {C}.
{T}, Sacrifice Untethered Spire: Choose target land card in your graveyard that was put there from the battlefield this turn. Return that card to your hand.

For each land you control, you may return a land card from your graveyard to the battlefield tapped.

Untrekked Territory enters tapped.
{T}: Add {B} or {G}.
When Untrekked Territory enters, you may put a loyalty counter on a planeswalker you control.

When Unwavering Sentinel enters, for each creature you control, create a white Aura enchantment token named Shield with “Enchant creature” and “If enchanted creature would be destroyed, instead remove all damage from it and sacrifice this Aura” attached to that creature.

When Unwitting Fanatic enters, create a 3/2 colorless Horror creature token.
Sacrifice Unwitting Fanatic: Another target permanent you control gains hexproof and indestructible until end of turn.

Choose one —
• Unwrite deals 3 damage to target attacking or blocking creature.
• Destroy target artifact.
• Destroy target enchantment.

Ward {1}
Other Scouts you control get +1/+1.
Whenever three or more Scouts you control attack, draw a card.

Unzari Ruins enters tapped.
{T}: Add {C}.
Tap five untapped creatures you control: Unzari Ruins becomes a 10/10 Construct artifact creature with trample until end of turn. It's still a land.

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

Constructs you control have haste.
When Urak, Voice of the Horde or another Construct you control enters, creatures you control get +1/+0 until end of turn.
Respawn (When this creature dies, if it attacked this turn, return it to its owner's hand.)

When Urn of Heroes enters, you may search your library for a legendary card, put that card into your graveyard, then shuffle.
{T}: Add {C}.

When Ursagore enters, you gain 4 life. Then if it was foreshadowed, create a 3/3 green Bear Spirit creature token.
When Ursagore dies, draw a card.
Foreshadow {5}{G}{G} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

You may have Urushi, the Ripple in the Smoke enter as a copy of any creature on the battlefield, except it's an enchantment. (It's not a creature.)

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
When Ushi Yun enters, create an Idol token.
As long as you're in a renaissance, artifacts you control have “{T}: Draw a card.”

Foretell {B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Destroy target creature or planeswalker. You lose 4 life unless this spell was foretold.

Foretell {X}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Gain control of target creature with power 2 or less. If this spell was foretold, gain control of target creature with power X or less instead.

Starting with the next opponent in turn order, each player sacrifices a permanent. Repeat this process until the total mana value of all permanents sacrificed this way is 13 or greater, or until thirteen or more permanents have been sacrificed this way, or until there are no nonland permanents on the battlefield, whichever happens first. Exile Utter Pandemonium.

Exile all lands. For each land card exiled this way, Uttermost Obliteration deals 1 damage to that land's controller.