Retreat to Coralhelm | Simic Growth Chamber | Skyshroud Ranger

Cards

Simic Growth Chamber in hand.
Retreat to Coralhelm and
Skyshroud Ranger on the battlefield (
Skyshroud Ranger without summoning sickness).

Activate
Skyshroud Ranger by tapping it, putting
Simic Growth Chamber from your hand onto the battlefield.
When
Simic Growth Chamber enters the battlefield, it and
Retreat to Coralhelm trigger.
Resolve the
Simic Growth Chamber trigger, returning itself from the battlefield to your hand.
Resolve the
Retreat to Coralhelm trigger, untapping
Skyshroud Ranger.
Repeat.