Sonic is dead, according to Sega's new release, The Murder of Sonic the Hedgehog. The game is an April Fool's gift, and The Murder of Sonic the Hedgehog is free on Steam.

The game takes a visual novel format and opens with Sonic dying on the Mirage Express during Amy Rose's murder mystery party held to celebrate her birthday. It's up to you, the player, to find out who killed Sonic and what sinister things are afoot.

As for whether this game is canononical, the answer is no. "This is not a Sonic Team title, but we strongly believe in the power of headcanon," the Steam description says.