Slimy Aquarium

When you unlock this door, manifest dread, then put a +1/+1 counter on that creature.
(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.)

Underwater Tunnel

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.)

Underwater Tunnel // Slimy Aquarium

Drowned Diner

When you unlock this door, draw three cards, then discard a card.
(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.)

Meat Locker

When you unlock this door, tap up to one target creature and put two stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
(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.)

Meat Locker // Drowned Diner

Fear of Lost Teeth

When Fear of Lost Teeth dies, it deals 1 damage to any target and you gain 1 life.

Island

Unstoppable Slasher

Deathtouch
Whenever Unstoppable Slasher deals combat damage to a player, they lose half their life, rounded up.
When Unstoppable Slasher dies, if it had no counters on it, return it to the battlefield tapped under its owner's control with two stun counters on it.

Innocuous Rat

When Innocuous Rat dies, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Twist Reality

Choose one —
• Counter target spell.
• Manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Creeping Peeper

{T}: Add {U}. Spend this mana only to cast an enchantment spell, unlock a door, or turn a permanent face up.

Eaten Alive

As an additional cost to cast this spell, sacrifice a creature or pay {3}{B}.
Exile target creature or planeswalker.

Raven of Fell Omens

Flying
Whenever you commit a crime, each opponent loses 1 life and you gain 1 life. This ability triggers only once each turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

Imprisoned in the Moon

Enchant creature, land, or planeswalker
Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.

Sporogenic Infection

Enchant creature
When Sporogenic Infection enters, target player sacrifices a creature of their choice other than enchanted creature.
When enchanted creature is dealt damage, destroy it.

Gleaming Barrier

Defender
When this creature dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Tunnel Surveyor

When Tunnel Surveyor enters, create a 1/1 white Glimmer enchantment creature token.

Clammy Prowler

Whenever Clammy Prowler attacks, another target attacking creature can't be blocked this turn.

Murky Sewer

Murky Sewer enters tapped unless a player has 13 or less life.
{T}: Add {U} or {B}.

Refute

Counter target spell. Draw a card, then discard a card.

Hero's Downfall

Nimble Brigand

Nimble Brigand can't be blocked if you've committed a crime this turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)
Whenever Nimble Brigand deals combat damage to a player, draw a card.

Let's Play a Game

Delirium — Choose one. If there are four or more card types among cards in your graveyard, choose one or more instead.
• Creatures your opponents control get -1/-1 until end of turn.
• Each opponent discards two cards.
• Each opponent loses 3 life and you gain 3 life.

Miasma Demon

Flying
When Miasma Demon enters, you may discard any number of cards. When you do, up to that many target creatures each get -2/-2 until end of turn.

Swamp

Balemurk Leech

Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, each opponent loses 1 life.

Give In to Violence

Target creature gets +2/+2 and gains lifelink until end of turn.

Fear of Infinity

Flying, lifelink
Fear of Infinity can't block.
Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, you may return Fear of Infinity from your graveyard to your hand.

Silent Hallcreeper

Silent Hallcreeper can't be blocked.
Whenever Silent Hallcreeper deals combat damage to a player, choose one that hasn't been chosen —
• Put two +1/+1 counters on Silent Hallcreeper.
• Draw a card.
• Silent Hallcreeper becomes a copy of another target creature you control.

Enduring Tenacity

Whenever you gain life, target opponent loses that much life.
When Enduring Tenacity dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Killer's Mask

When Killer's Mask enters, manifest dread, then attach Killer's Mask to that creature. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
Equipped creature has menace.
Equip {2}

Dismal Backwater

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {B}.

Get Out

Choose one —
• Counter target creature or enchantment spell.
• Return one or two target creatures and/or enchantments you own to your hand.

The Mindskinner

The Mindskinner can't be blocked.
If a source you control would deal damage to an opponent, prevent that damage and each opponent mills that many cards.

Spring Splasher

Whenever Spring Splasher attacks, target creature defending player controls gets -3/-0 until end of turn.

Osseous Sticktwister

Lifelink
Delirium — At the beginning of your end step, if there are four or more card types among cards in your graveyard, each opponent may sacrifice a nonland permanent of their choice or discard a card. Then Osseous Sticktwister deals damage equal to its power to each opponent who didn't sacrifice a permanent or discard a card this way.

Fake Your Own Death

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control and you create a Treasure token." (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Commune with Evil

Look at the top four cards of your library. Put one of them into your hand and the rest into your graveyard. You gain 3 life.

Witness Protection

Enchant creature
Enchanted creature loses all abilities and is a green and white Citizen creature with base power and toughness 1/1 named Legitimate Businessperson. (It loses all other colors, card types, creature types, and names.)

Enduring Curiosity

Flash
Whenever a creature you control deals combat damage to a player, draw a card.
When Enduring Curiosity dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)