Overview
Stone Stone (石石) is a hidden rare spirit in Roco Kingdom: World triggered at the Holy Feather Altar magic source on the Old Airship Route. It is one of the two spirits this statue can spawn.
How to Obtain
Teleport to the Holy Feather Altar Magic Source (圣羽祭台魔力之源) in Old Airship Route.
Approach the stone statue.
Throw a ground-type spirit at the statue. Stone Stone spawns around the statue.
Capture with any Gulu Ball.
Tips
Caterpillar uses the same statue with a water-type throw. Bring both a ground and a water spirit to complete both triggers in a single visit.
The throw does not consume the spirit in your party. A low-level ground-type works fine as the trigger.
See Also
Old Airship Route - spawn zone
Caterpillar - sibling statue trigger
Hidden Secrets and Collectibles - full hidden spirit list