Fog
From Starfy Wiki
Fog (Japanese: きり) reduces the visibility of the area in Densetsu no Starfy 3 and The Legendary Starfy. Fog is much thicker in Densetsu no Starfy 3 than it is in The Legendary Starfy.
Densetsu no Starfy 3
In Densetsu no Starfy 3, there are foggy areas in Misty Town. Starfy or Starly can use a Star Spin to create a circle around them where there is no fog. The circle can be made bigger by using multiple Star Spins but the circle will gradually get smaller when Starfy and Starly are not performing Star Spins.
The Legendary Starfy
In The Legendary Starfy, there are foggy areas of Sogwood Forest. Starfy can use the light of a Glowing Mushroom to create a star shaped area where there is no fog.