Great Whale and Shipwreck Dowser on the battlefield.
You control up to seven lands that can tap to produce at least ({2} magic symbol) ({U} magic symbol) .
Steps
Activate up to seven lands by tapping them, adding at least ({2} magic symbol) ({U} magic symbol) .
Cast Ghostly Flicker by paying ({2} magic symbol) ({U} magic symbol) , blinking Shipwreck Dowser and Great Whale.
When Shipwreck Dowser and Great Whale enter the battlefield, their abilities trigger.
Resolve the Shipwreck Dowser trigger, returning Ghostly Flicker to your hand from your graveyard.
Resolve the Great Whale trigger, untapping up to seven lands.
Repeat.
If you control seven lands that can tap to produce at least ({3} magic symbol) ({U} magic symbol) , this combo nets infinite mana, and you may blink any other permanent besides Great Whale.