Murasa Rootgrazer + Retreat to Coralhelm + Yarok, the Desecrated

Prerequisites

At least one basic land in hand. Murasa does not have summoning sickness.

Steps

1. Tap Rootgrazer, putting a basic land into play.
2. Retreat to Coralhelm triggers twice, in response, tap the basic for mana.
3. Let the first Retreat trigger resolve, untapping Rootgrazer.
4. Tap Rootgrazer, returning any basic you control to your hand.
5. Let the second Retreat trigger resolve, untapping Rootgrazer.
6. Repeat