How can you create a combo with Retreat to Coralhelm, Walking Atlas, Ghost Town?
user
[START OF COMBO]This combo can be formed with Retreat to Coralhelm, Walking Atlas, Ghost Town

Color identity: U
Mana cost: 
Steps:
  1. Activate Walking Atlas by tapping it, putting Ghost Town from your hand onto the battlefield.
  2. Retreat to Coralhelm triggers, untapping Walking Atlas.
  3. Activate Ghost Town by tapping it, adding {C}.
  4. Activate Ghost town by paying {0}, returning it to your hand.
  5. Repeat.[END OF COMBO STEPS]

Result:
  - Infinite colorless mana
  - Infinite landfall triggers[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Retreat to Coralhelm must be on the battlefield
  - Walking Atlas must be on the battlefield
  - Ghost Town must be in your hand
  - Walking Atlas does not have summoning sickness.
  - It is not your turn.
[END OF COMBO PREREQUISITES]
assistant