Crawl (Japanese: ハイハイ) is an ability only Starly can use. To use it move the control pad left or right while ducking. It is taught to her by the Hoki Group in Densetsu no Starfy 3. It is taught to her again by Runosaru in Densetsu no Starfy 4. Starly does not forget how to use it in The Legendary Starfy. It is mistranslated as "High Hat" in Super Smash Bros. Brawl.
Description from The Legendary Starfy
"Starly's small size lets her crawl through the smallest openings."