How can you create a combo with Prototype Portal, Retreat to Coralhelm, Ensoul Artifact, Treasure Vault?
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[START OF COMBO]This combo can be formed with Prototype Portal, Retreat to Coralhelm, Ensoul Artifact, Treasure Vault

Color identity: U
Mana cost: 
Steps:
  1. Activate Prototype Portal by tapping it, creating a token copy of Treasure Vault.
  2. When the Treasure Vault token enters the battlefield, Retreat to Coralhelm triggers, untapping Prototype Portal.
  3. Repeat.
  4. Once you have infinite Treasure Vault tokens, you may tap them for infinite mana, and then use a Treasure Vault to create infinite Treasure toknes.[END OF COMBO STEPS]

Result:
  - Infinite colored mana
  - Infinite colorless mana
  - Infinite landfall triggers
  - Infinite Treasure tokens
  - Infinite Treasure Vault tokens[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Prototype Portal must be on the battlefield
  - Retreat to Coralhelm must be on the battlefield
  - Ensoul Artifact must be on the battlefield
  - Treasure Vault must be exiled
  - Ensoul Artifact attached to Prototype Portal.
  - Prototype Portal does not have summoning sickness.
[END OF COMBO PREREQUISITES]
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