Launch Roblox and join Speed Run Obby. On the left-hand side, choose Settings, the little cog icon next to the Invite button. In Settings, scrolls down to find the code redemption window.

Naturally, this power extends to Shadow as well, so you'll be able to run beyond the speed of sound as his golden self in Sonic Speed Simulator on Roblox too, in a limited-time event.

Sonic is getting an official game on Roblox and it has Chaos! The “speed simulator” was made by Sega of America and Gamefam and allows you run around as Sonic, Tails, and Knuckles.