Exile target nonland permanent. You lose 3 life.

Apocalypse Hydra enters the battlefield with X +1/+1 counters on it. If X is 5 or more, it enters the battlefield with an additional X +1/+1 counters on it.

{1}{R}, Remove a +1/+1 counter from Apocalypse Hydra: It deals 1 damage to any target.

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

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Astral Cornucopia enters the battlefield with X charge counters on it.

{T}: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.

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

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

This spell costs {1} less to cast for each creature on the battlefield.

Blasphemous Act deals 13 damage to each creature.

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

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

As Breeding Pool enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

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

As Cavern of Souls enters the battlefield, choose a creature type.

{T}: Add {C}.

{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Lands you control have "{T}: Add one mana of any color."

{T}: Add one mana of any color.

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

Sacrifice Commander's Sphere: Draw a card.

You may play lands from your graveyard.

{T}: Choose target nonland permanent card in your graveyard. If you haven't cast a spell this turn, you may cast that card. If you do, you can't cast additional spells this turn. Activate only as a sorcery.

When Contagion Engine enters the battlefield, put a -1/-1 counter on each creature target player controls.

{4}, {T}: Proliferate, then proliferate again. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

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.")

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

Door to Nothingness enters the battlefield tapped.

{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice Door to Nothingness: Target player loses the game.

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Whenever you cast a spell with {X} in its mana cost, put two charge counters on Elementalist's Palette.

{T}: Add one mana of any color.

{T}: Add {C} for each charge counter on Elementalist's Palette. Spend this mana only on costs that contain {X}.

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

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)

Everflowing Chalice enters the battlefield with a charge counter on it for each time it was kicked.

{T}: Add {C} for each charge counter on Everflowing Chalice.

Landfall -- Whenever a land enters the battlefield under your control, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

You may play an additional land on each of your turns.

Look at the top three cards of your library. Put one of them into your hand, put one of them on the bottom of your library, and exile one of them. You may play the exiled card this turn.

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

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

When Garruk's Uprising enters the battlefield, if you control a creature with power 4 or greater, draw a card.

Creatures you control have trample. (They can deal excess combat damage to the player or planeswalker they're attacking.)

Whenever a creature with power 4 or greater enters the battlefield under your control, draw a card.

Look at the top five cards of your library. Put any number of permanent cards from among them onto the battlefield and the rest into your hand. Exile Genesis Ultimatum.

({T}: Add {W} or {U}.)

As Hallowed Fountain enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Shroud (This enchantment can't be the target of spells or abilities.)

{X}: Put X tower counters on Helix Pinnacle.

At the beginning of your upkeep, if there are 100 or more tower counters on Helix Pinnacle, you win the game.

{X}{X}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)

When Hydra Broodmaster becomes monstrous, create X X/X green Hydra creature tokens.

When you cast this spell, you gain half X life and draw half X cards. Round down each time.

Flying, trample

Hydroid Krasis enters the battlefield with X +1/+1 counters on it.

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

Indatha Triome enters the battlefield tapped.

Cycling {3} ({3}, Discard this card: Draw a card.)

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

({T}: Add {R}, {G}, or {W}.)

Jetmir's Garden enters the battlefield tapped.

Cycling {3} ({3}, Discard this card: Draw a card.)

Trample

Kalonian Hydra enters the battlefield with four +1/+1 counters on it.

Whenever Kalonian Hydra attacks, double the number of +1/+1 counters on each creature you control.

Activated abilities of artifacts your opponents control can't be activated.

+1: Until your next turn, up to one target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.

-2: You may reveal an artifact card you own from outside the game or choose a face-up artifact card you own in exile. Put that card into your hand.

Trample

Lifeblood Hydra enters the battlefield with X +1/+1 counters on it.

When Lifeblood Hydra dies, you gain life and draw cards equal to its power.

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.

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

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

If you tap a permanent for mana, it produces twice as much of that mana instead.

Trample

Whenever a player casts a spell, put a +1/+1 counter on Managorger Hydra.

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

At the beginning of your upkeep, put a +1/+1 counter on each creature you control if you control a creature with power 5 or greater. Then you gain 10 life if you control a creature with power 10 or greater. Then you win the game if you control a creature with power 20 or greater.

This spell can't be countered.

Haste, protection from blue

Mistcutter Hydra enters the battlefield with X +1/+1 counters on it.

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

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

Indestructible

As long as your devotion to green is less than five, Nylea isn't a creature. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)

Other creatures you control have trample.

{3}{G}: Target creature gets +2/+2 until end of turn.

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

As Overgrown Tomb enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

If damage would be dealt to Phyrexian Hydra, prevent that damage. Put a -1/-1 counter on Phyrexian Hydra for each 1 damage prevented this way.

({T}: Add {R} or {W}.)

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

Reach

{6}{W/P}: Transform Polukranos Reborn. Activate only as a sorcery. ({W/P} can be paid with either {W} or 2 life.)

Reach, lifelink

Whenever Polukranos, Engine of Ruin or another nontoken Hydra you control dies, create a 3/3 green and white Phyrexian Hydra creature token with reach and a 3/3 green and white Phyrexian Hydra creature token with lifelink.

Primordial Hydra enters the battlefield with X +1/+1 counters on it.

At the beginning of your upkeep, double the number of +1/+1 counters on Primordial Hydra.

Primordial Hydra has trample as long as it has ten or more +1/+1 counters on it.

Protection from everything

If Progenitus would be put into a graveyard from anywhere, reveal Progenitus and shuffle it into its owner's library instead.

Protean Hydra enters the battlefield with X +1/+1 counters on it.

If damage would be dealt to Protean Hydra, prevent that damage and remove that many +1/+1 counters from it.

Whenever a +1/+1 counter is removed from Protean Hydra, put two +1/+1 counters on it at the beginning of the next end step.

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Destroy all nonland permanents your opponents control.

({T}: Add {R} or {W}.)

As Sacred Foundry enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Double strike

Savageborn Hydra enters the battlefield with X +1/+1 counters on it.

{1}{R/G}: Put a +1/+1 counter on Savageborn Hydra. Activate only as a sorcery.

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

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

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

Flying, haste

Shivan Devastator enters the battlefield with X +1/+1 counters on it.

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

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

({T}: Add {G}, {W}, or {U}.)

Spara's Headquarters enters the battlefield tapped.

Cycling {3} ({3}, Discard this card: Draw a card.)

Annihilator 1 (Whenever this creature attacks, defending player sacrifices a permanent.)

{4}: Create two 0/1 colorless Eldrazi Spawn creature tokens. They have "Sacrifice this creature: Add {C}."

{20}: Cast any number of Eldrazi spells from among cards you own outside the game without paying their mana costs.

Search your library for a Plains, Island, Swamp, Mountain, or Forest card and put that card onto the battlefield. Then shuffle.

({T}: Add {U} or {R}.)

As Steam Vents enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Steelbane Hydra enters the battlefield with X +1/+1 counters on it.

{2}{G}, Remove a +1/+1 counter from Steelbane Hydra: Destroy target artifact or enchantment.

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

As Stomping Ground enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

This spell can't be countered.

Destroy all creatures.

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

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)

Exile Teferi's Protection.

Flying

The Goose Mother enters the battlefield with X +1/+1 counters on it.

When The Goose Mother enters the battlefield, create half X Food tokens, rounded up.

Whenever The Goose Mother attacks, you may sacrifice a Food. If you do, draw a card.

This spell costs {X} less to cast, where X is the greatest power among creatures you control.

{T}: Add {G}{G}. You gain 2 life.

Whenever a nontoken creature enters the battlefield under your control, put a +1/+1 counter on it and draw a card.

Indestructible

When The One Ring enters the battlefield, if you cast it, you gain protection from everything until your next turn.

At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring.

{T}: Put a burden counter on The One Ring, then draw a card for each burden counter on The One Ring.

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

({T}: Add {W} or {U}.)

Reach

Ulvenwald Hydra's power and toughness are each equal to the number of lands you control.

When Ulvenwald Hydra enters the battlefield, you may search your library for a land card, put it onto the battlefield tapped, then shuffle.

Whenever you cast a permanent spell with a mana cost that contains {X}, double the value of X.

Whenever you cast an instant or sorcery spell or activate an ability, if that spell's mana cost or that ability's activation cost contains {X}, copy that spell or ability. You may choose new targets for the copy.

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

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

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

Destroy target permanent.

This spell can't be countered.

Destroy target nonland permanent.

({T}: Add {U} or {R}.)

Trample

Voracious Hydra enters the battlefield with X +1/+1 counters on it.

When Voracious Hydra enters the battlefield, choose one --

• Double the number of +1/+1 counters on Voracious Hydra.

• Voracious Hydra fights target creature you don't control.

{G}{U}, {T}: Double the number of each kind of counter on target artifact, creature, or land.

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

As Watery Grave enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Reach

When Whiptongue Hydra enters the battlefield, destroy all creatures with flying. Put a +1/+1 counter on Whiptongue Hydra for each creature destroyed this way.

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

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

Search your library for a creature card, reveal it, then shuffle and put the card on top.

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

Zagoth Triome enters the battlefield tapped.

Cycling {3} ({3}, Discard this card: Draw a card.)

Deathtouch

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

Whenever you cast a spell with {X} in its mana cost, create a 0/0 green Hydra creature token, then put X +1/+1 counters on it.