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.)

Trample

Domain — Whenever Briar Hydra deals combat damage to a player, put X +1/+1 counters on target creature you control, where X is the number of basic land types among lands you control.

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

: Put a +1/+1 counter on Capricopian, then you may reselect which player Capricopian is attacking. Only the player Capricopian is attacking may activate this ability and only during the declare attackers step. (It can't attack its controller.)

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.

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.

At the beginning of each end step, if you rolled a die this turn,

Augment (, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

As Neverwinter Hydra enters the battlefield, roll X d6. It enters with a number of +1/+1 counters on it equal to the total of those results.

Trample

Ward (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays .)

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.

: 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.

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.

Vigilance, reach, trample

Ramunap Hydra gets +1/+1 as long as you control a Desert.

Ramunap Hydra gets +1/+1 as long as there is a Desert card in your graveyard.

Defender (This creature can't attack.)

Whenever Sprouting Phytohydra is dealt damage, you may create a token that's a copy of Sprouting Phytohydra.

When Stumpsquall Hydra enters the battlefield, distribute X +1/+1 counters among it and any number of commanders.

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.)