Sonic World Adventure (ソニックワールドアドベンチャー,Sonikku Wārudo Adobenchā?) is a two chapter story that was published by ASCII Media Works (MediaWorks) and featured in an issue of their Japanese gaming magazine Dengeki Nintendo DS. The manga picks up where Sonic transforms into the Sonic the Werehog. It roughly follows the storyline of Sonic Unleashed and features Chip tagging along with Sonic, similar to the game.
The manga begins as Sonic is transforming into the Werehog due to Doctor Eggman infusing him with Dark Gaia gas. Eggman then begins to brag about having done so as to get revenge on Sonic for always spoiling his schemes. Sonic simply taunts the doctor, challenging him to try all he wants, but no matter how hard he will try, he will always stop him. He proceeds to escape by breaking a wall with his newly-elongated arms. As Sonic is falling, he realizes how strong he has become from the transformation and promises himself that he will thank Eggman later.
The manga skips the part in the game where Sonic finds Chip lying next to him, and the next part begins with Sonic and Chip walking together. Chip states he is hungry, and Sonic agrees to stop in the next village for food. Excited, Chip rushes ahead of Sonic, shouting that he wants ice cream.
Once at the village, they head to an ice cream vendor. Chip arrives before Sonic and is so eager for his ice cream that he accidentally destroys the vendor's cart. Sonic shows up shortly afterward, only to see Chip complaining about not having found any ice cream and the vendor in tears. Sonic has an idea Chip probably did something, but only tells Chip and the vendor he will do something about the broken cart.
Chip rushes off with Sonic (the latter not what you could call thrilled about that) to help him find parts to mend the cart. Chip goes about happily searching for materials but finds food instead. Sonic scolds Chip, telling him now is not the time to look for food as they need to fix the vendor's cart, but Chip goes ahead picking apples for his ice cream. Sonic continues to scold him, but Chip ignores him and finds a strawberry. Sonic angrily kicks Chip in the head and leaves.
He finds some Egg Fighters and defeats them per usual. Chip comes back, and noticing the robot parts lying on the ground, mentions that they have collected a decent amount of parts. Sonic agrees and they quickly head back to the village.
After repairing the vendor's ice cream cart, they show him the results. Because of the robot parts, the cart is now fully automated, even speaking to the customers. Chip flies up to the cart, glad to be the first customer since its repairs. The new cart greets him, then proceeds to shoot him. Sonic and the vendor run away, as the cart begins to chase them down and shoot them as well.
This chapter begins as Sonic finishes destroying a group of Egg Fighters. Chip informs him that it is almost nighttime and so he will turn in the Werehog again. As there are more Egg Fighters to defeat, Sonic quickly runs towards them and destroys them with Chip hanging onto him. Chip tells Sonic that his first impression of him was that he was scary but gentle; Sonic then has a flashback.
The flashback starts at the part of the game when Sonic first meets Chip, which the manga had skipped earlier. Sonic is falling from the sky and lands on the ground. He gets up, saying that now he knows what it is like to fall from space without Tails there to catch him (possibly a reference to Sonic the Hedgehog 2). Sonic looks around him and sees Chip laying on the ground, and asks him if he is okay. Chip, asleep, says that he cannot eat anymore and wakes up. He looks up at Sonic, who smiles down at him, but since he has turned into the Werehog, his mouth has grown wider and with more, larger fangs. His smile scares Chip, who hides behind a rock, saying he is not tasty. Sonic does not let that bother him too much, and introduces himself to Chip and asks for his name. Chip cannot remember his name and says something fell out of the sky and knocked him unconscious which is why he cannot remember. Sonic wonders if he hit him when he fell and assures Chip that someone in the area will probably recognize him. The sun begins to shine, which causes Sonic to turn back into his normal self. This amazes Chip, and he questions Sonic about how that happened. Sonic replies that he does not know, then tells Chip that they should start looking for his memories. Chip agrees, and the flashback ends.
Sonic notices the moon has come up at this point, and he has turned back into the Werehog. The group of Egg Fighters from before is still after him, and he easily defeats them with his new abilities.
Chip cheers for Sonic, then says that now they can look for his memories since it was all Sonic's fault they were missing in the first place. He continues, talking about ice cream, but Sonic seems upset about Chip having made such a big deal about everything being his fault.