msem-instigator

At the beginning of your upkeep, each player mills two cards, then reveals the top card of their library and puts it on the bottom of their library.

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.)

Draw two cards. Then target opponent may give themselves two poison counters. If they don't, draw two cards.
{1}, Discard Unravel Prophecy: Add one mana of any color. Scry 1.

Choose one, then choose another for each card named Unraveling in your graveyard.
• Counter up to one target spell.
• Scry 2, then draw a card.
• Up to three target lands your opponents control don't untap during their controller's next untap step.
• Creatures your opponents control get -4/-0 until end of turn.

Unreflected Cultist can't be blocked by Reflections.

Choose one, then choose another for each card named Unrelenting in your graveyard.
• Creatures get -1/-1 until end of turn.
• Create a 2/2 blue Elemental creature token.
• Each opponent loses 3 life and you gain 3 life.
• Search your library for a card with mana value 4 or greater, reveal it, put it into your hand, then shuffle.

Trample, ward {1}
Whenever you gain life, put a +1/+1 counter on Unrelenting Noble.
{1}, Sacrifice a permanent: You gain 2 life.

This spell costs {2} less to cast if your starting deck contained at least forty cards more than the minimum deck size.
When Unrivaled Fireweaver enters, you may exile a red instant or sorcery card you own from outside the game. Until the end of your next turn, you may play that card.

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Unruly Magus deals combat damage to a player, draw a card.

Target attacking creature fights another target attacking creature.

Glitch—Sacrifice a creature. (Remove one [restriction] for each time you pay the glitch cost.)
When Unshackled Revolutionary enters, you may destroy target creature an opponent controls [with mana value 3 or less]. [You lose 3 life.]

All creatures get -2/-2 until end of turn. Add {B}{B}.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Unstable Borer attacks each combat if able.

Reverberate {2}{R} (When you cast this spell, copy it if you paid its reverberate cost.)
Creatures your opponents control get -2/-0 until end of turn. If Unstable Experiment is reverberated, creatures you control get +1/+0 until end of turn.

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.

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

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.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Unstoppable Weed gets +1/+1 for each +1/+1 counter on other creatures you control.

Trample
Whenever Unstoppable Zealot deals damage to a player or noncreature permanent, you may put a land card from your hand or graveyard onto the battlefield.

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.

Target creature you control gets +1/+0 until end of turn. That creature deals damage equal to its power to another target creature.

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

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever a creature you control becomes renowned, create a 1/1 red Soldier creature token with haste.