Nyxborn Hydra

a creature gets a counter — 2,691 cards in the game can cause this (Nyxborn Hydra is one).

When Nyxborn Hydra gets a counter:

1. Hollowmurk Siege — draws you 1 card
2. Ant-Man, Colony Commander — makes a token
3. Earth Kingdom General — gains you that much life
4. Casey Jones, Back Alley Brute — deals that much damage
5. Generous Patron — draws you 1 card
6. Shalai and Hallar — deals that much damage
7. Danny Pink — draws you 1 card
8. Enduring Scalelord — puts a +1/+1 counter on itself
9. Bold Plagiarist — puts counters on a permanent
10. Mikey & Leo, Chaos & Order — draws you 1 card

33 other cards care about it too. These are the ones with the most connections.

an enchantment is cast — 3,673 cards in the game can cause this (Nyxborn Hydra is one).

When Nyxborn Hydra is cast:

1. Hallowed Haunting — makes a token
2. Daxos the Returned — puts a counter on a permanent
3. Tatsunari, Toad Rider — makes a token
4. Sythis, Harvest's Hand — gains you 1 life
5. Sigil of the Empty Throne — makes a token
6. Dawnhart Geist — gains you 2 life
7. Herald of the Pantheon — gains you 1 life
8. Kami of Transience — puts a +1/+1 counter on itself
9. Argothian Enchantress — draws you 1 card
10. Mesa Enchantress — draws you 1 card

255 other cards care about it too. These are the ones with the most connections.

a nontoken enchantment enters the battlefield — 3,691 cards in the game can cause this (Nyxborn Hydra is one).

1. Historian's Boon — When Nyxborn Hydra enters, Historian's Boon makes a token

an enchantment enters the battlefield — 3,743 cards in the game can cause this (Nyxborn Hydra is one).

When Nyxborn Hydra enters:

1. Calix, Guided by Fate — puts a counter on a creature
2. Elvish Archivist — draws you 1 card
3. Victor, Valgavoth's Seneschal — surveils
4. Strength from the Fallen — gives +X/+X, where X is the number of creature cards in your graveyard
5. Doomwake Giant — shrinks a creature by -1/-1
6. Cacophony Unleashed — turns something into a creature
7. Ghostly Dancers — makes a token
8. Thassa's Devourer — mills a card
9. Killian, Decisive Mentor — taps a creature
10. Thoughtrender Lamia — makes an opponent discard a card

67 other cards care about it too. These are the ones with the most connections.

anything gets a counter — 4,415 cards in the game can cause this (Nyxborn Hydra is one).

1. All Will Be One — When Nyxborn Hydra gets a counter, All Will Be One deals that much damage

8 other cards care about it too. These are the ones with the most connections.

anything attacks — 17,934 cards in the game can cause this (Nyxborn Hydra is one).

When Nyxborn Hydra attacks:

1. Within Range — makes each opponent lose life
2. Sparring Regimen — puts a counter on a creature
3. Far Fortune, End Boss — deals 1 damage
4. Temmet, Naktamun's Will — draws you 1 card
5. Campsite Cuisine — sacrifices a Food
6. Obsessive Pursuit — makes you lose life
7. Invisible Woman — triggers
8. Caesar, Legion's Emperor — sacrifices a creature
9. Guide of Souls — triggers
10. Gossip's Talent — triggers

118 other cards care about it too. These are the ones with the most connections.

a creature attacks — 17,934 cards in the game can cause this (Nyxborn Hydra is one).

When Nyxborn Hydra attacks:

1. Adaptive Omnitool — searches a library
2. Anthem of Rakdos — gives +2/+0
3. Kindred Discovery — draws you 1 card
4. Invasion of New Capenna // Holy Frazzle-Cannon — puts counters on a permanent
5. Chorale of the Void — brings a card back
6. Saw — sacrifices a creature
7. Gisa's Favorite Shovel — makes an opponent sacrifice a creature
8. Ultima Weapon — kills a creature an opponent controls

184 other cards care about it too. These are the ones with the most connections.

a creature blocks — 17,934 cards in the game can cause this (Nyxborn Hydra is one).

1. Tide of War — When Nyxborn Hydra blocks, Tide of War sacrifices a creature

27 other cards care about it too. These are the ones with the most connections.

a creature is cast — 18,010 cards in the game can cause this (Nyxborn Hydra is one).

When Nyxborn Hydra is cast:

1. Primeval Bounty — makes a token
2. Communal Brewing — it arrives with counters thanks to Communal Brewing

89 other cards care about it too. These are the ones with the most connections.

a creature enters the battlefield — 19,800 cards in the game can cause this (Nyxborn Hydra is one).

When Nyxborn Hydra enters:

1. Airbender Ascension — puts a quest counter on itself
2. Slash, Reptile Rampager — deals 2 damage
3. The Neutrinos — gets +1/+0
4. Wingnut, Bat on the Belfry — grants flying, haste and menace
5. Aetherstorm Roc — puts a counter on a permanent you control
6. Raphael, Most Attitude — exiles a card from your library

331 other cards care about it too. These are the ones with the most connections.

anything enters the battlefield — 26,499 cards in the game can cause this (Nyxborn Hydra is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When Nyxborn Hydra enters, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself

50 other cards care about it too. These are the ones with the most connections.