How can you create a combo with Scaretiller, Retreat to Coralhelm, Gateway Plaza, Urza, Lord High Artificer?
user
[START OF COMBO]This combo can be formed with Scaretiller, Retreat to Coralhelm, Gateway Plaza, Urza, Lord High Artificer

Color identity: U
Mana cost: 
Steps:
  1. Activate Urza by tapping Scaretiller, adding {U}.
  2. Scaretiller triggers, returning Gateway Plaza from your graveyard to the battlefield tapped.
  3. Gateway Plaza enters the battlefield, triggering itself and Retreat to Coralhelm.
  4. Resolve the Gateway Plaza trigger, choosing to sacrifice it.
  5. Resolve the Retreat to Coralhelm trigger, untapping Scaretiller.
  6. Repeat.[END OF COMBO STEPS]

Result:
  - Infinite blue mana
  - Infinite landfall triggers
  - Infinite tap triggers
  - Play all cards in your library without paying their mana costs[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Scaretiller must be on the battlefield
  - Retreat to Coralhelm must be on the battlefield
  - Gateway Plaza must be in the graveyard
  - Urza, Lord High Artificer must be on the battlefield
[END OF COMBO PREREQUISITES]
assistant