Sporocyst

a Tyranid deals combat damage — 91 cards in the game can cause this (Sporocyst is one).

1. Tyranid Harridan — When Sporocyst deals combat damage, Tyranid Harridan makes a token

a land enters the battlefield — 1,560 cards in the game can cause this (Sporocyst is one).

When a land enters thanks to Sporocyst:

1. Primeval Bounty — gains you 3 life
2. Toph, Earthbending Master — puts a counter on a permanent
3. Dancing from Dark to Dawn — makes a token
4. Emeria Shepherd — brings a card back
5. Quest for the Necropolis — puts a quest counter on itself
6. Soul Stair Expedition — puts a quest counter on itself
7. Nissa of Shadowed Boughs — puts counters on a permanent
8. Thranduil, Sindarin Liege // Silvan Rally — makes a token
9. Silvan Reveler — returns itself from the graveyard
10. Floral Evoker — puts a +1/+1 counter on itself

199 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 (Sporocyst is one).

When Sporocyst attacks:

1. Far Fortune, End Boss — deals 1 damage
2. Temmet, Naktamun's Will — draws you 1 card
3. Grim Javelineer — gives +1/+0
4. Invisible Woman — triggers
5. Caesar, Legion's Emperor — sacrifices a creature
6. Guide of Souls — triggers
7. Campsite Cuisine — sacrifices a Food
8. Gossip's Talent — triggers
9. Banon, the Returners' Leader — draws and discards
10. Three Dog, Galaxy News DJ — sacrifices an Aura

111 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 (Sporocyst is one).

When Sporocyst 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. Anim Pakal, Thousandth Moon — puts a +1/+1 counter on itself
7. Saw — sacrifices a creature
8. Gisa's Favorite Shovel — makes an opponent sacrifice a creature
9. Ultima Weapon — kills a creature an opponent controls
10. Total War — kills a creature

180 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 (Sporocyst is one).

When Sporocyst blocks:

1. Mage Hunters' Onslaught — makes a player lose 1 life
2. Carnage Gladiator — makes a player lose 1 life
3. Perimeter Captain — gains you 2 life
4. Tide of War — sacrifices a creature
5. Dead-Iron Sledge — kills a creature
6. Dwindle — kills a creature

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

a creature deals combat damage — 17,934 cards in the game can cause this (Sporocyst is one).

1. Primo, the Unbounded — When Sporocyst deals combat damage, Primo, the Unbounded makes a token

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

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

1. Mardu Ascendancy — When Sporocyst attacks, Mardu Ascendancy makes a token

2 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 (Sporocyst is one).

When Sporocyst enters:

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

305 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 (Sporocyst is one).

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

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