The Key to Babylon Garden is an object that appears in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. It was an ancient Babylonian artifact. It was originally one of two components that made up the ignition matrix of the Babylon Garden.
After the ancient Babylonians crash-landed on Mobius long ago, they removed the ignition matrix and separated its two components to prevent the Garden from being reactivated, as due to a malfunction its activation would destroy the planet. The Key was placed in a hidden location under the Gigan Mountains and guarded by Angelus.
In 3237, the Babylon Rogues discovered a book in ancient Babylonian that revealed the location of the Key. Not knowing the truth of Babylon Garden, Jet the Hawk only wished to obtain the Key to gain personal glory. Ignoring the warning given by Angelus, Jet removed the Key, causing energy signatures to resonate. This lead to the Key falling into the possession of the Battle Lord, who owned its partner component, the Gravity Ring. Placing the Ring into the Key revealed the location of Babylon Garden, now buried deep beneath New Mobotropolis. The Battle Bird Armada and the Babylon Rogues attacked New Mobotropolis to gain access to the Garden, and the Rogues placed the combined Ring and Key into the Garden's systems, reactivating it and causing it to rise from beneath the ground. However, it was then realized that reactivating the Garden would cause a black hole to form, as per Angelus' warning, and destroy Mobius itself; while Jet, Wave, Storm and Speedy debated on a course of action, Sonic the Hedgehog removed the ignition matrix and destroyed both the Key and Ring. Losing power, the Babylon Garden crashed into the mountains.