Vigilance

When Undermountain Adventurer enters, you take the initiative.

: Add . If you've completed a dungeon, add six instead.

Flash (You may cast this spell any time you could cast an instant.)

Undersea Invader enters tapped.

When you unlock this door, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Underworld Charger can't block.

Escape—, Exile three other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Underworld Charger escapes with two +1/+1 counters on it.

Underworld Rage-Hound attacks each combat if able.

Escape—, Exile three other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Underworld Rage-Hound escapes with a +1/+1 counter on it.

When Undying Beast dies, put it on top of its owner's library.

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Return target creature card with mana value 3 or less from your graveyard to the battlefield.

Cycling (, Discard this card: Draw a card.)

Target nontoken creature you control gets +2/+0 and gains double team until end of turn. It also gains first strike until end of turn if it has the same name as another creature you control or a creature card in your graveyard.

As an additional cost to cast this spell, discard a card.

Draw two cards and create two Treasure tokens. (They're artifacts with ", Sacrifice this artifact: Add one mana of any color.")

For each player, exile up to one target nonland permanent that player controls. For each permanent exiled this way, its controller cloaks the top card of their library. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward . Turn it face up any time for its mana cost if it's a creature card.)

Draw three cards.

Adamant — If at least three blue mana was spent to cast this spell, scry 3.

Enchant creature

Enchanted creature gets +2/+2 and has trample and lifelink. (Damage dealt by the creature also causes its controller to gain that much life.)

2 — : Add . Spend this mana only to cast creature spells.

4 — At the beginning of combat on your turn, target noncreature artifact you control becomes a 4/4 artifact creature with flying until end of turn.

2 — 2/4

5 — 8/6

Enchant creature

When enchanted creature dies, return that card to the battlefield under your control.

2 — : You gain 1 life.

4 — Whenever this creature attacks, tap each creature an opponent controls with the same power and/or same toughness as this creature.

2 — 4/1

3 — 2/6

Black legendary creatures you control have "bands with other legendary creatures." (Any legendary creatures can attack in a band as long as at least one has "bands with other legendary creatures." Bands are blocked as a group. If at least two legendary creatures you control, one of which has "bands with other legendary creatures," are blocking or being blocked by the same creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Vigilance

: Put a +1/+1 counter on Unholy Officiant.

Unimpeded Trespasser can't be blocked.

2 — : Add one mana of any color.

3 — Whenever this creature attacks, if it's not a Brushwagg, it gets +X/+0 until end of turn, where X is the number of supertypes, card types, and subtypes it has.

2 — 5/1

4 — 4/8

Changeling (This card is every creature type.)

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for .)

Draw X cards.

Double the power of target creature until end of turn.

Unleash the Inferno deals 7 damage to target creature or planeswalker. When it deals excess damage this way, destroy target artifact or enchantment an opponent controls with mana value less than or equal to that amount of excess damage.

: Exile up to two target cards from a single graveyard.

Unlicensed Hearse's power and toughness are each equal to the number of cards exiled with it.

Crew 2

: Target nonattacking, nonblocking creature gets +0/+2 until end of turn.

: Unliving Psychopath gets +1/-1 until end of turn.

, : Destroy target creature with power less than Unliving Psychopath's power.

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.)

Return up to two target creature cards from your graveyard to your hand.

You may exile a black card from your hand rather than pay this spell's mana cost.

Target player reveals their hand. You choose a nonland card from it. That player discards that card.

Devoid (This card has no color.)

Target creature gets +2/+0 until end of turn. Regenerate it.

Enchant creature

At the beginning of the upkeep of enchanted creature's controller, Unnatural Hunger deals damage equal to that creature's power to that player unless they sacrifice another creature of their choice.

Target creature gets +1/+1 and gains trample until end of turn.

: Choose a creature type other than Wall. Target creature becomes that type until end of turn.

Creatures your opponents control get -1/-0 until end of turn if was spent to cast this spell, and creatures you control get +1/+0 until end of turn if was spent to cast this spell. (Do both if was spent.)

If a cycling ability of another nonland card would cause you to draw a card, instead exile cards from the top of your library until you exile a card that shares a card type with the cycled card. You may cast that card without paying its mana cost. Then put the exiled cards that weren't cast this way on the bottom of your library in a random order.

Cycling (, Discard this card: Draw a card.)

Enchant creature

When Unquenchable Thirst enters, if you control a Desert or there is a Desert card in your graveyard, tap enchanted creature.

Enchanted creature doesn't untap during its controller's untap step.

Choose target artifact or enchantment. Its owner shuffles it into their library.

Defender

: Unruly Catapult deals 1 damage to each opponent.

Whenever you cast an instant or sorcery spell, untap Unruly Catapult.

2 — Whenever this creature attacks, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

4 — Indestructible

2 — 3/2

3 — 5/4

When Unscrupulous Contractor enters, you may sacrifice a creature. When you do, target player draws two cards and loses 2 life.

Plot (You may pay and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)

: Target creature gains forestwalk until end of turn.

When Unshakable Tail enters and at the beginning of your upkeep, surveil 1.

Whenever one or more creature cards are put into your graveyard from your library, investigate. (Create a Clue token. It's an artifact with ", Sacrifice this artifact: Draw a card.")

, Sacrifice a Clue: Return Unshakable Tail from your graveyard to your hand.

When Unstable Amulet enters, you get (two energy counters).

Whenever you cast a spell from anywhere other than your hand, Unstable Amulet deals 1 damage to each opponent.

, Pay : Exile the top card of your library. You may play it until you exile another card with Unstable Amulet.

: Add .

: Target land you control becomes the basic land type of your choice until end of turn.

Morph (You may cast this card face down as a 2/2 creature for . Turn it face up any time for its morph cost.)

When Unstable Hulk is turned face up, it gets +6/+6 and gains trample until end of turn. You skip your next turn.

: Add .

, , Sacrifice Unstable Obelisk: Destroy target permanent.

Whenever another creature enters, Unstable Shapeshifter becomes a copy of that creature, except it has this ability.

When Unstoppable Ogre enters, target creature can't block this turn.

Return target spell or creature to its owner's hand.

Enchant creature

Enchanted creature gets +2/+1 and has menace. (It can't be blocked except by two or more creatures.)