Sonic hasn't had much time for his old enemies recently. In the free-to-play runner Sonic Dash, he has spent most of his time fighting off Zavok, Zazz, and other strangely named members of the Deadly Six.
However, a new update has brought with it a blast from the past, in the form of one Dr. Eggman, otherwise known as Sonic's original nemesis Dr. Robotnik.
In the new Dr. Eggman Boss Battle sections, you have to guide Sonic around a series of traps, and avoid attacks from the levitating, goggle-sporting maniac. You'll even get to leap into the air and sabotage the lunatic's signature hoverchair.
You can download the Sonic Dash update for free right now. In fact, the game itself is free - with the requisite collection of ads and IAPs, of course.