Key to the Side-Door

a card is discarded — 2,042 cards in the game can cause this (Key to the Side-Door is one).

When a permanent makes a player discard a card thanks to Key to the Side-Door:

1. Ivora, Insatiable Heir — puts a +1/+1 counter on itself
2. Cool but Rude — deals 2 damage
3. Containment Construct — brings a card back
4. Moonstone, Harsh Mistress — brings a card back
5. Lazotep Chancellor — puts 2 counters on a Zombie or Army
6. Magmakin Artillerist — deals that much damage
7. Inti, Seneschal of the Sun — exiles a card from your library
8. Pitchstone Wall — sacrifices itself
9. Currency Converter — exiles it
10. Hostile Investigator — triggers

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

an artifact is cast — 3,683 cards in the game can cause this (Key to the Side-Door is one).

When Key to the Side-Door is cast:

1. Mendicant Core, Guidelight — copies a spell
2. Sai, Master Thopterist — makes a token
3. Ravenous Robots — makes a token
4. Pinnacle Emissary — makes a token
5. Mirrodin Besieged — makes a token
6. Poetic Ingenuity — makes a token
7. Digsite Engineer — makes a token
8. Myrsmith — makes a token
9. Riddlesmith — draws you 1 card
10. Dr. Madison Li — puts a counter on a permanent you control

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

a nontoken artifact enters the battlefield — 3,768 cards in the game can cause this (Key to the Side-Door is one).

When Key to the Side-Door enters:

1. Ultron, Artificial Malevolence — makes a token
2. The Prydwen, Steel Flagship — makes a token
3. Conquest Mission — puts a quest counter on itself
4. Surge Conductor — proliferates
5. Replication Specialist — makes a token
6. Weapons Manufacturing — makes a token
7. Mirrorworks — makes a token

a card is drawn — 3,815 cards in the game can cause this (Key to the Side-Door is one).

When Key to the Side-Door makes a player draw a card:

1. Temmet, Naktamun's Will — gives +1/+1
2. Niv-Mizzet, Parun — deals 1 damage
3. Aether Syphon — mills a card
4. The Locust God — makes a token
5. Starving Revenant — makes each opponent lose 1 life
6. Diviner's Wand — gets +1/+1
7. Ominous Seas — puts a foreshadow counter on itself
8. Dream Trawler — gets +1/+0
9. Iron Man, Armored Avenger — puts a counter on a creature
10. The Astonishing Ant-Man — puts a +1/+1 counter on itself

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

an artifact enters the battlefield — 4,643 cards in the game can cause this (Key to the Side-Door is one).

When Key to the Side-Door enters:

1. Transplant Theorist — draws you 1 card
2. Elvish Archivist — puts 2 +1/+1 counters on itself
3. Golbez, Crystal Collector — surveils
4. Sludge Strider — makes a player lose 1 life
5. Underhanded Designs — makes each opponent lose 1 life
6. Mechan Assembler — makes a token
7. Glassdust Hulk — gets +1/+1
8. Rook Turret — draws you 1 card
9. Hedron Detonator — deals 1 damage
10. Pactdoll Terror — makes each opponent lose 1 life

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

a card in a graveyard — 7,589 cards in the game can cause this (Key to the Side-Door is one).

Key to the Side-Door:

1. Tergrid, God of Fright // Tergrid's Lantern — puts cards into the graveyard that Tergrid, God of Fright // Tergrid's Lantern can bring back
2. Vessel of Endless Rest — puts cards into the graveyard that Vessel of Endless Rest can bring back
3. Samwise Gamgee — puts cards into the graveyard that Samwise Gamgee can bring back
4. Bloodbond March — puts cards into the graveyard that Bloodbond March can bring back
5. Gale, Waterdeep Prodigy — puts cards into the graveyard that Gale, Waterdeep Prodigy can bring back
6. Harness the Storm — puts cards into the graveyard that Harness the Storm can bring back
7. Heart-Shaped Herb — puts cards into the graveyard that Heart-Shaped Herb can bring back
8. Wayward Angel — fills your graveyard toward the 7 or more cards Wayward Angel needs
9. Rescue from the Underworld — puts cards into the graveyard that Rescue from the Underworld can bring back
10. Victimize — puts cards into the graveyard that Victimize 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 the game can cause this (Key to the Side-Door is one).

When a card hits the graveyard thanks to Key to the Side-Door:

1. Quest for Ancient Secrets — puts a quest counter on itself
2. Measure of Wickedness — gives an opponent control of itself
3. Energy Field — sacrifices itself

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