Satoru Umezawa and Coiling Stalker on the battlefield.
Coiling Stalker does not have summoning sickness and cannot be blocked by an opponent.
You control up to seven lands that can tap to produce at least ({3} magic symbol) ({B} magic symbol) ({G} magic symbol) ({U} magic symbol) .
Steps
Declare Coiling Stalker as an attacker.
When it isn't blocked, activate up to seven lands you control by tapping them, adding at least ({3} magic symbol) ({B} magic symbol) ({G} magic symbol) ({U} magic symbol) .
Activate Great Whale's ninjutsu ability by paying ({2} magic symbol) ({U} magic symbol) ({B} magic symbol) and returning Coiling Stalker from the battlefield to your hand, putting Great Whale onto the battlefield from your hand tapped and attacking.
When Great Whale enters the battlefield, it triggers, untapping up to seven lands.
Activate Coiling Stalker's ninjutsu ability by paying ({1} magic symbol) ({G} magic symbol) and returning Great Whale from the battlefield to your hand, putting Coiling Stalker onto the battlefield from your hand tapped and attacking.
Repeat from step 2.
If you control up to seven lands that can tap to produce at least ({4} magic symbol) ({B} magic symbol) ({G} magic symbol) ({U} magic symbol) , this combo nets infinite mana.