Sonic is a blue hedgehog with white gloves, a brown bandana around his neck, red shoes, white bandages around his hands, and very fast.
Sonic saved Mark and Treecko from Pokémon that were controlled by Darkrai. After that he lead them to his house before Mark got caught in a trap by Sticks as Sonic told her he's with him.
Sonic also guide them to Amy, and Knuckles. Who question Mark and Treecko. Froakie who suddenly appeared told everyone he will guide them to Hydro Village. After more fights with more Pokémon they went to Hydro Village with Froakoe telling them info of course.
Sonic ask Froakie if their is a good amount of water in Hydro Village. When Froakie said tbis is about 75% of it he sarcasticly said "Ggggrrrreeeeaaaattttt."
When they reached a waterfall he ask "Why does not surprise me?" Much to Mark, Treecko, and Froakie's confusion. After the gang explained everything with Knuckles explaining if he is in water Sonic glared at him.
Sonic told everyone to watch out that danger lurks around Hydro Cave. They then took a ride from a current and soon it was over. (Much to Sonic's releif.) They were attacked by Druddigon after they defeated him he confessed that two Pokémon tricked him.