Cascade, cascade, cascade, cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order. Multiple instances of cascade each trigger separately.)

Balduvian Hydra enters the battlefield with X +1/+0 counters on it.

Remove a +1/+0 counter from Balduvian Hydra: Prevent the next 1 damage that would be dealt to Balduvian Hydra this turn.

: Put a +1/+0 counter on Balduvian Hydra. Activate only during your upkeep.

Trample

Bioessence Hydra enters the battlefield with a +1/+1 counter on it for each loyalty counter on planeswalkers you control.

Whenever one or more loyalty counters are put on planeswalkers you control, put that many +1/+1 counters on Bioessence Hydra.

When Bristling Hydra enters the battlefield, you get (three energy counters).

Pay : Put a +1/+1 counter on Bristling Hydra. It gains hexproof until end of turn.

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

Whenever Clockwork Hydra attacks or blocks, remove a +1/+1 counter from it. If you do, Clockwork Hydra deals 1 damage to any target.

: Put a +1/+1 counter on Clockwork Hydra.

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

: Put a +1/+1 counter on Feral Hydra. Any player may activate this ability.

When you cast this spell, reveal the top X cards of your library. You may put a nonland permanent card with mana value X or less from among them onto the battlefield. Then shuffle the rest into your library.

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

Grakmaw, Skyclave Ravager enters the battlefield with three +1/+1 counters on it.

Whenever another creature you control dies, if it had a +1/+1 counter on it, put a +1/+1 counter on Grakmaw.

When Grakmaw dies, create an X/X black and green Hydra creature token, where X is the number of +1/+1 counters on Grakmaw.

Heroes' Bane enters the battlefield with four +1/+1 counters on it.

: Put X +1/+1 counters on Heroes' Bane, where X is its power.

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

When Hooded Hydra dies, create a 1/1 green Snake creature token for each +1/+1 counter on it.

Morph

As Hooded Hydra is turned face up, put five +1/+1 counters on it.

: 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.

As Hydradoodle enters the battlefield, roll X six-sided dice. Hydradoodle enters the battlefield with a number of +1/+1 counters on it equal to the total of those results.

Reach, trample

If a creature would deal combat damage to Ironscale Hydra, prevent that damage and put a +1/+1 counter on Ironscale Hydra.

This spell costs less to cast for each green creature you control.

Trample

Trample

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

: Put a +1/+1 counter on Molten Hydra.

, Remove all +1/+1 counters from Molten Hydra: It deals damage to any target equal to the number of +1/+1 counters removed this way.

Tribute 6 (As this creature enters the battlefield, an opponent of your choice may put six +1/+1 counters on it.)

When Nessian Wilds Ravager enters the battlefield, if tribute wasn't paid, you may have Nessian Wilds Ravager fight another target creature. (Each deals damage equal to its power to the other.)

Trample

Landfall — Whenever a land enters the battlefield under your control, put a +1/+1 counter on Oran-Rief Hydra. If that land is a Forest, put two +1/+1 counters on Oran-Rief Hydra instead.

If damage would be dealt to Phytohydra, put that many +1/+1 counters on it instead.

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.

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

When Polukranos, World Eater becomes monstrous, it deals X damage divided as you choose among any number of target creatures your opponents control. Each of those creatures deals damage equal to its power to Polukranos.

Protection from everything

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

Rampant Rejuvenator enters the battlefield with two +1/+1 counters on it.

When Rampant Rejuvenator dies, search your library for up to X basic land cards, where X is Rampant Rejuvenator's power, put them onto the battlefield, then shuffle.

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

For each 1 damage that would be dealt to Rock Hydra, if it has a +1/+1 counter on it, remove a +1/+1 counter from it and prevent that 1 damage.

: Prevent the next 1 damage that would be dealt to Rock Hydra this turn.

: Put a +1/+1 counter on Rock Hydra. Activate only during your upkeep.

Trample

Scourge of Skola Vale enters the battlefield with two +1/+1 counters on it.

, Sacrifice another creature: Put a number of +1/+1 counters on Scourge of Skola Vale equal to the sacrificed creature's toughness.

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

, Remove a +1/+1 counter from Spitting Hydra: It deals 1 damage to target creature.

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

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

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.

Ulasht, the Hate Seed enters the battlefield with a +1/+1 counter on it for each other red creature you control and a +1/+1 counter on it for each other green creature you control.

, Remove a +1/+1 counter from Ulasht: Choose one —

• Ulasht deals 1 damage to target creature.

• Create a 1/1 green Saproling creature token.

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

When Vastwood Hydra dies, you may distribute a number of +1/+1 counters equal to the number of +1/+1 counters on Vastwood Hydra among any number of creatures you control.

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.

Reach

Wren's Run Hydra enters the battlefield with X +1/+1 counters on it.

Reinforce X— (, Discard this card: Put X +1/+1 counters on target creature.)