Froggy

"Froggy... Where are you?"

- Big the Cat calling for Froggy

Froggy (カエルくん) is a large green frog with yellow eyes with black pupils, dark green stripes, a light green belly, and is the pet and best friend of Big the Cat.

Game Appearances
During the course of Sonic Adventure and part of Sonic X, Froggy swallows both a part of Chaos and a Chaos Emerald. Abducted by E-102 Gamma, Froggy was taken to the Egg Carrier as Doctor Eggman wanted the Emerald and Chaos piece inside him. Big pursued him, and recovered his friend. However, the Chaos Emerald and the part of Chaos he had swallowed were absorbed into Chaos, allowing it to become Chaos 6, but was eventually rescued by Big with the aid of Sonic. Big and Froggy then took the Tornado 2 back to Mystic Ruins.

Sonic Heroes
In Sonic Heroes, Froggy and Chocola, a Chao, were abducted. Big, Amy and Cream went to look for them under the impression that Sonic had taken them. During the adventure they instead figured out that Eggman had kidnapped Froggy and Chocola, and defeated him. However, it turned out that Metal Sonic had framed Eggman, and had kidnapped Froggy and the Chao in order to copy the residual data of Chaos. Froggy was not seen in the final scenes of the game, but it can be assumed that he and Big went back to Mystic Ruins.

Sonic Chronicles: The Dark Brotherhood
He appears in Sonic Chronicles: The Dark Brotherhood in some of Big's POW moves. In an optional mission, it is known that Froggy has a friend who is also a frog named Norton the Frog. Froggy hadn't seen Norton in a while and was concerned about him. In the process of trying to find Norton, his other friends, Gally, Mr. Billywick, and Mrs. Stevens are found (and appear to have very active social lives, according to Big's dialogue).

Sonic & Sega All-Stars Racing
In Sonic & Sega All-Stars Racing, Froggy returns as Big's All-Star Move. After Froggy hopped on Big's head, he suddenly turns into Giant Froggy. Big's all-star theme is and...Fish Hits! from Sonic Adventure.

Theory

 * An interesting suggestion is that Froggy originates from "Frog Forest," a level in Sonic Heroes, which has giant frogs that can summon forth rain and bear a very strong resemblance to Froggy. If the player stands around in Frog Forest for some time as Team Rose, Big himself also presents this theory.

Trivia

 * Froggy is a quick swimmer.
 * Froggy is only one of four minor characters to have his own toy, the others being standard Chao, Cheese the Chao and Kiki.
 * In the beginning of Big's story in Sonic Adventure, Froggy had a short tail, but it grew bigger after his connection to Chaos. In almost every game he's appeared in after that, his tail remains the same size.
 * In the DS version of Sonic Colors, Big is seen looking for Froggy in the Aquarium Park. After he sends Sonic on a mission to look for him, Sonic says he didn't see him. It's unknown if Big found Froggy after this.
 * Froggy has had both orange stripes and dark green stripes on his body. It seems he has green stripes in art and orange stripes in-game.
 * In all games Froggy has appeared in he croaks like a normal frog, but in Sonic X he says "Ribbit" in English instead.