Sand clouds are an object in Super Mario World and its Game Boy Advance remake Super Mario World: Super Mario Advance 2.
Description[]

Super Mario World screenshot of Yellow Yoshi defeating a Rex with sand clouds
Sand clouds are puffs that a Yoshis of any color can create if they have either a Yellow Shell or a Flashing Shell and land after performing a jump, defeating any enemies nearby. A Yellow Yoshi can create sand clouds regardless of which color the Koopa Shell in its mouth is.