Price$1.29 – $4.28
Buy on TCGplayerCloud Key
Artifact
LegalRank #639
As this artifact enters, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost 
less to cast.
Why is this card good?
Cloud Key is a focused cost reducer that pays off hard in decks built around a single spell type. Unlike rocks that ramp you once, this shaves a generic mana off every spell of your chosen type for the rest of the game — the math compounds fast in a dedicated shell.
Where it shines:
- Spellslinger (instants/sorceries): chain more spells per turn, fuel storm/Magecraft commanders like Veyran or Krark/Sakashima.
- Artifact decks: Urza, Emry, Osgir, or any high-density affinity build.
- Enchantress (Sythis, Tuvasa) and creature-heavy go-wide token decks also benefit.
The strength is reliability: it stacks with other reducers (Helm of Awakening, Foundry Inspector, Goblin Electromancer) toward "free" spell turns.
When NOT to play it: any deck without ~15+ cards of one type. A 3-mana rock that doesn't ramp and reduces only a fraction of your spells is just bad — you'd rather run Mind Stone or Arcane Signet. It also does nothing the turn it lands, so it's weak in low-curve aggressive lists.
Related cards
Semblance Anvil
Imprints a type to reduce same-type spell costs, similar cost-reduction engine.
Helm of Awakening
Reduces all spell costs by {1}, broad cost reducer.
Etherium Sculptor
Reduces artifact spell costs by {1}, classic artifact discount.
Foundry Inspector
Reduces artifact spell costs by {1}, stackable artifact ramp.
Goblin Electromancer
Reduces instant and sorcery costs by {1}, spellslinger discount.
Jhoira's Familiar
Reduces artifact, instant, sorcery costs by {1} with flying body.
Urza's Incubator
Names a creature type to reduce those creature spell costs by {2}.
Herald's Horn
Names a creature type for {1} cost reduction plus card advantage.
Printings (7)
Played by these commanders
Inspirit, Flagship Vessel100% of 1
Combos (8)
- Sensei's Divining Top + Cloud Key + Mystic Forge
→ Infinite card draw, Near-infinite storm count, Infinite draw triggers
- Sensei's Divining Top + Cloud Key + The Reality Chip
→ Infinite card draw, Infinite draw triggers, Near-infinite storm count
- Scrap Trawler + Myr Retriever + Krark-Clan Ironworks + Cloud Key
→ Infinite ETB, Infinite LTB, Infinite colorless mana
- Sensei's Divining Top + Cloud Key + Crystal Skull, Isu Spyglass
→ Infinite card draw, Near-infinite storm count, Infinite draw triggers
- Scrap Trawler + Myr Retriever + Ashnod's Altar + Cloud Key
→ Infinite ETB, Infinite LTB, Infinite colorless mana
- Urza, Lord High Artificer + Forensic Gadgeteer + Sensei's Divining Top + Cloud Key
→ Infinite card draw, Infinite draw triggers, Near-infinite storm count
Rulings (2)
- 2021-03-19
The cost reduction applies only to generic mana in the cost of spells of the chosen type you cast.
- 2021-03-19
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as a flashback cost), add any cost increases (such as kicker costs), then apply any cost reductions (such as that of Cloud Key's ability). The mana value of the spell is determined by only its mana cost, no matter what the total cost to cast that spell was.