Vhal without summoning sickness and with toughness 5 or greater).
Easy Prerequisites
You have a land card in hand.
You are able to play a land this turn.
Steps
Play any land, triggering
Retreat to Coralhelm, targeting
Gogo.
Holding priority, activate
Vhal by tapping it, adding at least ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) that cannot be spent to cast spells from your hand.
Activate
Gogo by paying ({4} magic symbol) and tapping it, copying the
Retreat to Coralhelm trigger, targeting
Gogo and
Vhal.
Resolve both copies of the
Retreat to Coralhelm abilities, untapping
Gogo and
Vhal.
Repeat from step 2.
Results
Infinite untap of creatures you control.
Infinite mana creatures you control can produce.
Infinite colorless mana that cannot be spent to cast spells from your hand.