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.

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

{T}: Add one mana of any color in your commander's color identity.

Flying {T}: Add one mana of any color.

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Add {B}{B}{B}.

{1}, {T}: Add {U}{B}.

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

{1}, {T}: Add {B}{G}.

Draw a card. You may put a land card from your hand onto the battlefield.

As this artifact enters, choose a creature type. Creature spells you cast of the chosen type cost {1} less to cast. At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Black spells you cast cost {1} less to cast.

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

{T}: Add {C}{C}.

You have no maximum hand size. {T}: Add {C}.

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost. Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

({T}: Add {B} or {G}.)

This land enters tapped. When this land enters, exile target player's graveyard. {T}: Add {B}.

{2}, {T}: Add {B} for each Swamp you control.

{T}: Add one mana of any color in your commander's color identity.

This land enters tapped unless you control two or more other lands. {T}: Add {B} or {G}.

This land enters tapped. When this land enters, return a land you control to its owner's hand. {T}: Add {U}{B}.

This land enters tapped unless you control two or more other lands. {T}: Add {G} or {U}.

This land enters tapped unless you control an Island or a Swamp. {T}: Add {U} or {B}.

This land enters tapped. When this land enters, sacrifice it unless you return an untapped Swamp you control to its owner's hand. {T}: Add {C}{B}.

{T}: Add one mana of any color that a land an opponent controls could produce.

This land enters tapped. When this land enters, return a land you control to its owner's hand. {T}: Add {B}{G}.

This land enters tapped unless you have two or more opponents. {T}: Add {U} or {B}.

This land enters tapped. {T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

This land enters tapped unless you have two or more opponents. {T}: Add {G} or {U}.

You have no maximum hand size. {T}: Add {C}.

This land enters tapped unless you control two or more other lands. {T}: Add {U} or {B}.

{T}: Add {B}. {B}, {T}: Target legendary creature gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

This land enters tapped. When this land enters, return a land you control to its owner's hand. {T}: Add {G}{U}.

({T}: Add {U} or {B}.) This land enters tapped unless you control two or more basic lands.

({T}: Add {B}.)

This land enters tapped unless you have two or more opponents. {T}: Add {B} or {G}.

Each land is a Swamp in addition to its other land types.

{T}, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep. You draw a card at the beginning of the next turn's upkeep.

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Counter target spell.

Return target nonland permanent you don't control to its owner's hand. Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

If you control a commander, you may cast this spell without paying its mana cost. Exile target creature.

If you control a commander, you may cast this spell without paying its mana cost. Counter target noncreature spell.

Return all noncreature, nonland permanents to their owners' hands.

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Counter target noncreature spell.

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

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

Whenever another nontoken creature dies, you may create a 1/1 black Rat creature token. Rats you control have deathtouch.

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

Creatures you control have flying, first strike, vigilance, trample, haste, and protection from black and from red.

Commander creatures you own have "Whenever this creature becomes tapped, it and other creatures you control that share a creature type with it each get +2/+0 and gain undying until end of turn." (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Search your library for a card, put that card into your hand, then shuffle.

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.