Requires

Steps

1. Play Petrified Field.
2. When Petrified Field enters the battlefield, Kodama of the East Tree and Felidar Retreat trigger.
3. Resolve the Kodama of the East Tree trigger, putting nothing onto the battlefield.
4. Holding priority, activate Petrified Field's second ability by tapping and sacrificing it, returning Echoing Deeps from your graveyard to your hand.
5. Resolve the Felidar Retreat trigger, creating a 2/2 Cat Beast creature token.
6. When the creature token enters the battlefield, Kodama of the East Tree triggers, putting Echoing Deeps from your hand onto the battlefield untapped due to Spelunking as a copy of Petrified Field.
7. When Echoing Deeps enters the battlefield, Felidar Retreat triggers.
8. Holding priority, activate Echoing Deeps using Petrified Field's second ability by tapping and sacrificing it, returning Petrified Field from your graveyard to your hand.
9. Resolve the Felidar Retreat trigger, creating a 2/2 Cat Beast creature token.
10. When the creature token enters the battlefield, Kodama of the East Tree triggers, putting Petrified Field from your hand onto the battlefield.
11. When Petrified Field enters the battlefield, Felidar Retreat triggers.
12. Repeat from step 4.

Results