Sonic the Hedgehog was originally a game character and hero in many games created by Sega for the Sega Genesis. Artist Naoto Oshima, designer Hirokazu Yasuhara and programmer Yuji Naka are credited with the creation of Sonic, the blue anthropomorphic hedgehog, who can run faster than the speed of sound. That is one of the major factors of the games, in case you didn't know.
Sonic was created when the time came for Sega to get a new mascot, as Alex Kidd, a monkey boy with over-sized ears, was getting a little old. At first, Sonic, or "Mr. Needlemouse", as he was known in concept stage, wasn't the only character to be considered as the new mascot, but obviously he won out.
He had competition for the mascot position from the likes of Mighty the Armadillo and Ristar, which you probably haven't heard of, which shows just how much more popular Sonic became than those games. The color of Sonic was chosen to coincide with Sega's cobalt blue logo.
Upon the first inception of Sonic, a team comprised of fifteen people worked on it, with the soundtrack being composed by Masato Nakamura from the band Dreams Come True. In a joint venture, Sega went on to sponsor one of the band's tours. In return for this, Sega was allowed to paint Sonic on the band's bus, and hand out flyers and other promotional media before concerts, as well as play game footage on the stage before concerts.
Throughout the years, Sonic has remained the same character, but has a different look and feel to him depending on the designers and artists on the "Sonic Team", as they call themselves, at the time. Sonic's original presentation, designed by Ohshima, was very short, childlike, had short quills, and had a round body. Artwork using Ohshima's design was drawn by Akira Wantabe and was used on the package artwork for Sonic the Hedgehog.
Many games following this original game also used similar designs. Starting with Sonic Adventure in 1998, Sonic was redesigned by Yuji Uekawa and now appeared as a taller hedgehog with longer legs and a less spherical body, longer and more drooping spikes, and green-colored eyes. More, but less noticeable changes to Sonic's design have been made in many of the following games.
Spin-off media such as cartoons, flash games, and the like all use the basic designs that were used by the "Sonic Team" designers, but they also have their own unique look and feel to them.
Sonic's debut came in 1991 with the release of the platform game Sonic the Hedgehog, which is also referred to as Sonic 1, for the Sega Genesis. This game also featured Sonic's nemesis, Dr. Robotnik, who was renamed Dr. Eggman after a while. Next in the long line of Sonic games, came Sonic 2, which introduced Sonic's Super Sonic form and his soon to be signature Spin Dash. Sonic's sidekick, the lovable character known as Tails, was also introduced in this game. Sonic 2 was released in 1992. A year later, came Sonic CD, which introduced Amy Rose, Sonic's girlfriend, and Metal Sonic, Sonic's future counterpart.
This installment of the Sonic series involved Sonic traveling through time in order to save the world. Both Sonic the Hedgehog 3, and its sequel Sonic & Knuckles, were both released the following year in 1994. In Sonic 3, Sonic and Tails once again had to fight the evil Dr. Robotnik, and in Sonic & Knuckles, Sonic had to battle against Knuckles the Echidna, who had been tricked by Dr. Robotnik into fighting Sonic in the first place.
Next came many minor games which seem to foretell the end of the Sonic era, with releases such as Sonic Chaos, Sonic Triple Trouble, Sonic Blast, and Sonic the Hedgehog Pocket Adventure. Next, though, the "Sonic Team" got back in the saddle and produced another major Sonic game, this one being Sonic Adventure, which was release in 1998.
This is the first game that had a full voice over for Sonic, and was also the first time in the western releases that Dr. Robotnik was called Dr. Eggman. The next game didn't come until 2001, and it was Sonic Adventure 2. In Sonic Adventure 2, you play as Sonic who has been mistaken for a new military enemy called Shadow, who incidentally, does look a lot like Sonic, except for the color. It's probably because the fact that they are both hedgehogs, but I could be wrong, though.
After this game, Sonic made his move to the Nintendo handheld devices with the releases of Sonic Advance in 2001, and Sonic Advance 2 in 2002. After this, game Sonic Heroes for the Game Cube, which had Sonic, Shadow, Tails, and other characters teaming up to fight against a new Metal Sonic, whom has betrayed his master. After Sonic Heroes, we see the little blue hedgehog return the Game Boys with the releases of Sonic Advance 3 in 2004, and Sonic Rush in 2005. 2006 found Sonic in the underwater city of Soleanna, where he has to rescue Princess Elise from Dr. Eggman while avoiding Silver the Hedgehog, his newest nemesis.
In the next year, we got another installment of Sonic in Game Boy with Sonic Rush Adventure, we also got a more of an RPG look at Sonic with Sonic and the Secret Rings, where he helped a ring genie to collect the seven world rings and defeat the evil Erazor Djinn.
Sonic has also been made into many television series. Four out of five of these series have been released in the USA. The series names were Adventures of Sonic the Hedgehog, which featured lessons for kids, Sonic the Hedgehog, Sonic Underground, and Sonic X. In the first two series, Adventures of Sonic the Hedgehog, and Sonic the Hedgehog, Jaleel White was the voice of Sonic. He has also appeared many times in the printed media front, as well as the visual media front. Sonic's first appearance was in a promo comic in Disney Adventures magazine.
This comic showed the origins of the entire Sonic saga, and also shockingly revealed that Sonic originally was brown. Many British publications including Stay Sonic, and Sonic the Comic were based on this idea that Sonic was originally brown. Archie Comics produced the American comics of Sonic, Sonic the Hedgehog, which started in 1993, and Sonic X, which started more recently in 2005, both of which are still running today, and both are also based on their TV show counterparts.
The Sonic the Hedgehog series is the second longest running licensed comic series in the history of American comic books to Marvel's Conan. Two comic books in France have also been published; they were called Sonic Adventures, and Sonic manga has also been released in Japan. Apart from traditional print, and visual media, Sonic has also been featured in loads of flash games, ranging from re-makes of the 2D plat former style, to RPGs, and everything in around and in between.