Haunt of the Dead Marshes

a Nightmare enters the battlefield — 151 cards in the game can cause this (Haunt of the Dead Marshes is one).

1. Umbris, Fear Manifest — When Haunt of the Dead Marshes enters, Umbris, Fear Manifest exiles a card from an opponent's library

you scry — 420 cards in the game can cause this (Haunt of the Dead Marshes is one).

When Haunt of the Dead Marshes scries:

1. Prudent Fateseer // Peer Review — gives +1/+0
2. Diviner of Victory // Unwind History — gets +1/+1
3. Saheeli, Consul of Oversight — makes a token
4. Celeborn the Wise — makes your creatures bigger
5. Proft, Consulting Detective — puts a +1/+1 counter on itself
6. Matoya, Archon Elder — draws you 1 card
7. Denzilore Fatehold — puts a counter on a creature
8. Elminster — costs less
9. Elrond, Master of Healing — puts a counter on a creature
10. Galadriel of Lothlórien — puts a land onto the battlefield

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

an Elf attacks — 723 cards in the game can cause this (Haunt of the Dead Marshes is one).

When Haunt of the Dead Marshes attacks:

1. Tyvar the Bellicose — grants deathtouch
2. Harald Unites the Elves — shrinks a creature by -1/-1
3. Arboreal Alliance — triggers

1 other card cares about it too. These are the ones with the most connections.

a nontoken Elf enters the battlefield — 728 cards in the game can cause this (Haunt of the Dead Marshes is one).

1. Wirewood Hivemaster — When Haunt of the Dead Marshes enters, Wirewood Hivemaster makes a token

an Elf enters the battlefield — 752 cards in the game can cause this (Haunt of the Dead Marshes is one).

When Haunt of the Dead Marshes enters:

1. Wolverine Riders — gains you its toughness life
2. Elvish Warmaster — makes a token
3. Elvish Vanguard — puts a +1/+1 counter on itself
4. Marwyn, the Nurturer — puts a +1/+1 counter on itself
5. Woodland Weavemaster — gets +1/+1
6. High Perfect Morcant — puts a counter on a permanent an opponent controls
7. Maralen, Fae Ascendant — exiles a card from an opponent's library

1 other card cares about it too. These are the ones with the most connections.

a creature leaves a graveyard — 1,302 cards in the game can cause this (Haunt of the Dead Marshes is one).

When Haunt of the Dead Marshes leaves a graveyard:

1. Grim Reaper's Scythe — makes a token
2. Syr Konrad, the Grim — deals 1 damage
3. Cyan, Vengeful Samurai — puts a +1/+1 counter on itself
4. Along the Crooked Way — puts a counter on a Goblin or Army
5. Skeleton Crew — makes a token
6. Desecrated Tomb — makes a token
7. Chalk Outline — makes a token
8. Insidious Roots — makes a token
9. Undead Hand Ninja — makes each opponent lose 1 life
10. Erebos's Titan — triggers

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

anything leaves a graveyard — 2,503 cards in the game can cause this (Haunt of the Dead Marshes is one).

When Haunt of the Dead Marshes leaves a graveyard:

1. Blastoneuron — makes each opponent lose 1 life
2. Defiled Crypt // Cadaver Lab — makes a token
3. Teval, the Balanced Scale — makes a token
4. Hologram Stalker — makes a token
5. Tormod, the Desecrator — makes a token
6. Quintorius, Field Historian — makes a token
7. Garrison Excavator — makes a token
8. Amzu, Swarm's Hunger — makes a token
9. Kirol, History Buff // Pack a Punch — becomes prepared
10. Teval's Judgment — triggers

13 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 (Haunt of the Dead Marshes is one).

When Haunt of the Dead Marshes attacks:

1. Far Fortune, End Boss — deals 1 damage
2. Temmet, Naktamun's Will — draws you 1 card
3. Invisible Woman — triggers
4. Caesar, Legion's Emperor — sacrifices a creature
5. Guide of Souls — triggers
6. Campsite Cuisine — sacrifices a Food
7. Gossip's Talent — triggers

119 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 (Haunt of the Dead Marshes is one).

When Haunt of the Dead Marshes attacks:

1. Adaptive Omnitool — searches a library
2. Saw — sacrifices a creature

189 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 (Haunt of the Dead Marshes is one).

1. Tide of War — When Haunt of the Dead Marshes blocks, Tide of War sacrifices a creature

27 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 (Haunt of the Dead Marshes is one).

When Haunt of the Dead Marshes enters:

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

303 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 (Haunt of the Dead Marshes is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When Haunt of the Dead Marshes enters, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself

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