Scion of the Ur-Dragon

a permanent goes to a graveyard — 161 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

1. Grolnok, the Omnivore — When a Dragon hits the graveyard thanks to Scion of the Ur-Dragon, Grolnok, the Omnivore exiles it

a Dragon attacks — 474 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

When Scion of the Ur-Dragon attacks:

1. Silumgar, the Drifting Death — shrinks a creature by -1/-1
2. Utvara Hellkite — makes a token
3. The Ur-Dragon — draws you that many cards
4. Atarka, World Render — grants double strike
5. Kolaghan, the Storm's Fury — gives +1/+0
6. Invasion of Tarkir // Defiant Thundermaw — deals 2 damage
7. Ojutai, Soul of Winter — taps a creature, artifact, enchantment, planeswalker or battle an opponent controls
8. Dromoka, the Eternal — puts a counter on a permanent

a Dragon deals combat damage — 474 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

When Scion of the Ur-Dragon deals combat damage:

1. Parapet Thrasher — triggers
2. Broodcaller Scourge — puts a permanent onto the battlefield
3. Zurgo and Ojutai — triggers

a nontoken Dragon enters the battlefield — 484 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

When Scion of the Ur-Dragon enters:

1. Lathliss, Dragon Queen — makes a token
2. Miirym, Sentinel Wyrm — makes a token

a Dragon enters the battlefield — 524 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

When Scion of the Ur-Dragon enters:

1. Dragon Tempest — deals damage
2. Bloomvine Regent // Claim Territory — gains you 3 life
3. Sarkhan, Dragon Ascendant — puts a +1/+1 counter on itself
4. Ganax, Astral Hunter — makes a token
5. Scourge of Valkas — deals damage
6. Bladewing's Thrall — returns itself from the graveyard
7. Sarkhan, Soul Aflame — copies a permanent
8. Teeming Dragonstorm — triggers
9. Corroding Dragonstorm — triggers
10. Roiling Dragonstorm — triggers

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

a card in a graveyard — 7,589 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

Scion of the Ur-Dragon:

1. Gale, Waterdeep Prodigy — puts cards into the graveyard that Gale, Waterdeep Prodigy can bring back
2. Transplant Theorist — puts cards into the graveyard that Transplant Theorist can bring back
3. Heart-Shaped Herb — puts cards into the graveyard that Heart-Shaped Herb can bring back
4. Wayward Angel — fills your graveyard toward the 7 or more cards Wayward Angel needs
5. Rescue from the Underworld — puts cards into the graveyard that Rescue from the Underworld can bring back
6. Victimize — puts cards into the graveyard that Victimize can bring back
7. Bound // Determined — puts cards into the graveyard that Bound // Determined can bring back
8. Enlightened Confidant — puts cards into the graveyard that Enlightened Confidant can bring back
9. Tergrid, God of Fright // Tergrid's Lantern — puts cards into the graveyard that Tergrid, God of Fright // Tergrid's Lantern can bring back
10. Aerith, Last Ancient — puts cards into the graveyard that Aerith, Last Ancient can bring back

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

anything goes to a graveyard — 7,589 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

When a Dragon hits the graveyard thanks to Scion of the Ur-Dragon:

1. The Haunt of Hightower — puts a +1/+1 counter on itself
2. Duskmantle Guildmage — makes each opponent lose 1 life
3. Devourer of Memory — gets +1/+1
4. Polluted Cistern // Dim Oubliette — makes each opponent lose life
5. Vulturous Zombie — puts a +1/+1 counter on itself
6. Quest for Ancient Secrets — puts a quest counter on itself
7. Bloodchief Ascension — makes each opponent lose 2 life
8. Planar Void — hits a graveyard
9. Measure of Wickedness — gives an opponent control of itself
10. Energy Field — sacrifices itself

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

anything attacks — 17,934 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

When Scion of the Ur-Dragon 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

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

a creature attacks — 17,934 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

When Scion of the Ur-Dragon attacks:

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

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

a creature is cast — 18,010 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

1. Bloodbond March — When Scion of the Ur-Dragon is cast, Bloodbond March brings a card back

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

a nontoken creature enters the battlefield — 18,448 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

1. Samwise Gamgee — When Scion of the Ur-Dragon enters, Samwise Gamgee makes a token

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

a creature enters the battlefield — 19,800 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

When Scion of the Ur-Dragon enters:

1. Slash, Reptile Rampager — deals 2 damage
2. Gimli of the Glittering Caves — puts counters on a permanent
3. Ray Fillet, Wave Warrior — puts a counter on itself
4. Legolas Greenleaf — puts a counter on a permanent
5. The Neutrinos — gets +1/+0
6. Aetherstorm Roc — puts a counter on a permanent you control

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

anything enters the battlefield — 26,499 cards in Scion of the Ur-Dragon's colors can cause this (Scion of the Ur-Dragon is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When Scion of the Ur-Dragon enters, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself

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