Gogo, Master of Mimicry | High Tide | Retreat to Coralhelm (and two other cards)

Cards

High Tide and
Relm's Sketching in hand.
All permanents on the battlefield (
Invasion of Arcavios as
Invocation of the Founders and
Gogo without summoning sickness).

({4} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) available.

Cast
High Tide by paying ({U} magic symbol) .
Cast
Relm's Sketching by paying its mana cost, targeting an Island you control.
Invocation of the Founders triggers.
Holding priority, activate
Gogo by paying ({2} magic symbol) and tapping it, copying the
Invocation of the Founders ability.
Resolve the copy of
Invocation of the Founders's ability, copying the
Relm's Sketching spell, targeting an Island you control that enters the battlefield untapped.
Resolve the copy of
Relm's Sketching, creating a token copy of the targeted Island.
When the Island token enters,
Retreat to Coralhelm triggers, untapping
Gogo.
Activate the Island token by tapping it, adding ({U} magic symbol) .
High Tide triggers, adding ({U} magic symbol) .
Repeat from step 4.

This combo has been estimated to be Exhibition (Bracket 1+).