Thread:ITVdude2000/@comment-12498802-20160524171856/@comment-12498802-20160612104745

(Deep breath)

Eggman mass-produces robots called "Cybos", one of which escapes the lab, flies away due to a propeller modification he was given during production, only to bump into Tails on his hoverboard and help him find the Chaos Emeralds and Super Emeralds.

And after you beat the game, based on how quickly you finish it and how few Game Overs you receive, you may see an image where Tails is seen building a Cybo robot of his own, probably the one in Adventure 3.