As an additional cost to cast this spell, sacrifice a creature. Draw two cards.

Whenever Ayara or another black creature you control enters, each opponent loses 1 life and you gain 1 life. {T}, Sacrifice another black creature: Draw a card.

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.) Other Rats you control have toxic 1. When Karumonix enters, look at the top five cards of your library. You may reveal any number of Rat cards from among them and put the revealed cards into your hand. Put the rest on the bottom of your library in a random order.

At the beginning of your upkeep, you draw a card and you lose 1 life.

{T}, Sacrifice two other creatures: Any number of target players each lose 2 life and sacrifice a creature of their choice. You add {B}{B} and draw a card.

Equipped creature gets +1/-1. Whenever equipped creature dies, draw two cards. Equip {1}

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.

As this artifact enters, choose a creature type. Creatures you control of the chosen type get +1/+1. Whenever you cast a creature spell of the chosen type, draw a card.

Changeling (This card is every creature type.) This creature can't block and can't be blocked.

Whenever a creature attacks you, its controller loses 1 life.

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.) Equip {0}

Whenever another Rat you control enters, exile up to one target card from an opponent's graveyard. At the beginning of combat on your turn, create a 1/1 black Rat creature token with "This token can't block."

Pestilence Rats's power is equal to the number of other Rats on the battlefield. (For example, as long as there are two other Rats on the battlefield, Pestilence Rats's power and toughness are 2/3.)

This creature gets +1/+0 for each other Rat you control. A deck can have any number of cards named Rat Colony.

This creature gets +1/+1 for each other creature on the battlefield named Relentless Rats. A deck can have any number of cards named Relentless Rats.

Swarm of Rats's power is equal to the number of Rats you control.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) When this creature enters, each player gets a poison counter.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) Whenever this creature attacks, if defending player is poisoned, it gets +1/+1 until end of turn.

As this artifact enters, choose artifact, creature, enchantment, instant, or sorcery. Spells you cast of the chosen type cost {1} less to cast.

Add {B}{B}{B}.

As this artifact enters, choose a color. Creatures you control of the chosen color get +1/+0. {T}: Add one mana of the chosen color.

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

Each opponent's maximum hand size is reduced by one.

Each opponent's maximum hand size is reduced by two.

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.) Whenever this creature deals combat damage to a player, that player discards two cards.

Pack Rat's power and toughness are each equal to the number of Rats you control. {2}{B}, Discard a card: Create a token that's a copy of this creature.

When this creature enters, each player discards a card. Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Target creature gets -1/-1 until end of turn for each Swamp you control.

Destroy target nonartifact creature.

Destroy target creature or planeswalker.

Destroy target creature. You lose 2 life.

Choose a creature type. Destroy all creatures that aren't of the chosen type.

All creatures get -1/-1 until end of turn for each Swamp you control.

Deathtouch When this creature dies, exile target card from an opponent's graveyard.

Ninjutsu {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.) Whenever this creature deals combat damage to a player, destroy target nonblack creature that player controls.

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

When this enchantment enters, create a 1/1 white Human Soldier creature token. Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

Whenever this creature or another creature dies, target player loses 1 life and you gain 1 life.

Target opponent loses 1 life for each attacking creature you control. You gain that much life.