Fly Guy

Fly Guys is a subspecies of Shy Guy from the Marioverse. Controversly, these has been named 'Shy Guys' in Smash games.

In Super Smash Bros.
In Super Smash Bros., they flew back and forth in the background of the Yoshi's Island stage, sometimes with a fruit.

In Super Smash Bros. Melee
They got a more noteworthy appearance in Super Smash Bros. Melee. The appeard as enemies on the Yoshi's Story stage carrying food and even was featured on the Shy Guy trophy. The stage Yoshi's Island from Super Smash Bros. was also converted into Melee and renamed Past Stage: Yoshi's Island, still included with the Fly Guys.

In Super Smash Bros. Brawl
They reappers as background characters in their Yoshi's Island DS design on the Yoshi's Island stage.