Cast Croaking Counterpart by paying ({1} magic symbol) ({G} magic symbol) ({U} magic symbol) , creating a token copy of Wildwood Scourge that is a 1/1 Frog.
Put a +1/+1 counter on either Wildwood Scourge.
The Wildwood Scourge who didn't have the counter put on it triggers, putting a +1/+1 counter on itself.