Frightened Heart
From Starfy Wiki
The Frightened Hearts (Japanese: おびえるココロ) are objects in Densetsu no Starfy 4. They are found in Dejiru's Castle (Stage 9-1). In the story, Okubyonomon asks Starfy to destroy them, as part of the 'Test of Courage' (Japanese: ゆうきのしれん). Removing all of the Frightened Hearts will banish Shinigami and remove the curse on Okubyonomon, turning it back to Yukinomon.
There are 25 Frightened Hearts spread across four rooms. Each Frightened Heart can be destroyed with a Star Spin. Some of the Frightened Hearts are wearing a helmet, and take an additional Star Spin for Starfy to defeat.
As a reward for destroying the Frightened Hearts, Yukinomon opens the door leading to Mayoinomon and rewards Starfy, Starly and Moe with the Dejiru's Dress Treasure.