No, it wasn’t an April Fool’s joke by Sega / Sony when a DLC pack for Sega’s Sonic & Sega All-Stars Racing
popped up on the UK PlayStation Network and later disappeared on April 1. The pack, which added Metal Sonic as a playable racer and the Egg Hangar race track to the game, appeared for a short amount of time before being yanked away. Some gamers were able to get a hold of it before the download was erased. It turns out that this was an error as the the DLC is officially launching sometime in the future.
Sega has kind-of, sort-of, unofficially addressed the situation on their European blog
and noted that a pack will be available soon which will only contain Ryo Sazuki and his forklift. THe posting states that this is the “only DLC item" available right now and to “stay tuned for further details on ASR DLC". This pack was recently only available to those who pre-ordered the game as a bonus, but can now be purchased by everyone. Forget Metal Sonic, I want the Dwarf from Golden Axe... give me Gillius!