Vigilance
Hydra spells you cast cost less to cast.
Whenever a creature you control becomes the target of a spell, "Legendary Hydration" fights up to one target creature you don't control.

Choose one —
• Exile target creature with power 3 or greater.
• You draw two cards and you lose 2 life.
• Distribute two +1/+1 counters among one or two target creatures.

Creatures you control have trample.
Creatures your opponents control lose trample and can't have or gain trample.

Monocolored creatures can't block this turn.

When Baffling End enters the battlefield, exile target creature an opponent controls with converted mana cost 3 or less.
When Baffling End leaves the battlefield, target opponent creates a 3/3 green Dinosaur creature token with trample.

Exile up to three target enchantments.
Cycling (, Discard this card: Draw a card.)

Devoid (This card has no color.)
Ingest (Whenever this creature deals combat damage to a player, that player exiles the top card of their library.)
Benthic Infiltrator can't be blocked.

Until end of turn, gain control of target creature and it gains haste. Untap and goad that creature. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

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.

Assist (Another player can pay up to of this spell's cost.)
When Bloodborn Scoundrels enters the battlefield, target opponent loses 2 life and you gain 2 life.

Target player mills eight cards.
Fuse (You may cast one or both halves of this card from your hand.)

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token that's a copy of this creature that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Whenever Broodbirth Viper deals combat damage to a player, you may draw a card.

Whenever you cast a noncreature spell, Burning Prophet gets +1/+0 until end of turn, then scry 1.

Return target nonland permanent to its owner's hand.
Amass 1. (Put a +1/+1 counter on an Army you control. If you don't control one, create a 0/0 black Zombie Army creature token first.)

Counter target spell.

When Careless Celebrant dies, it deals 2 damage to target creature or planeswalker an opponent controls.

Whenever you activate a loyalty ability of a Chandra planeswalker, you may pay . If you do, copy that ability. You may choose new targets for the copy.
, , Discard a Mountain card or a red card: Draw a card.

Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle their library.
Draw a card.

Target player mills four cards. You draw a card for each creature card put into their graveyard this way.

Enchant creature
When Colossification enters the battlefield, tap enchanted creature.
Enchanted creature gets +20/+20.