How can you create a combo with Prototype Portal, Ugin's Nexus, Grinding Station?
user
[START OF COMBO]This combo can be formed with Prototype Portal, Ugin's Nexus, Grinding Station

Color identity: C
Mana cost: {5} each turn
Steps:
  1. Activate Prototype Portal by paying {5} and tapping it, creating a token copy of Ugin's Nexus.
  2. When the Ugin's Nexus token enters the battlefield, Grinding Station triggers, untapping Grinding Station.
  3. Activate Grinding Station by tapping it and sacrificing the Ugin's Nexus token.
  4. The Ugin's Nexus token is exiled instead of being put into your graveyard, causing you to take an extra turn after this one.
  5. Resolve the Grinding Station ability, causing target player to mill three cards.
  6. Repeat each turn.[END OF COMBO STEPS]

Result:
  - Infinite turns[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Prototype Portal must be on the battlefield
  - Ugin's Nexus must be exiled
  - Grinding Station must be on the battlefield
[END OF COMBO PREREQUISITES]
assistant