Franchise: Sonic The Hedgehog

The skid noise made when Sonic stops running comes from Out Run, an earlier SEGA game.

Fang the Sniper, called Nack the Weasel in the English release of Sonic Triple Trouble and various English-language comic books, originally wielded a realistic gun. However, this was considered too violent for the Sonic series, and was changed to a cork-shooting popgun during development of his debut game, Sonic Triple Trouble.

According to the Archie comics, Sonic the Hedgehog's real name was originally "Olgilvie Maurice Hedgehog", and was meant to act as a part of a never-used plot. However, due to one of the comic writers leaving the staff, this concept was never touched upon, and was eventually retconned as Sonic legally changing his name at an early age, leaving his actual first name a mystery.

This would later be referenced years later, where the Netflix description for the animated series "Sonic Prime" claimed that Sonic's middle name was Maurice.

Sticks the Badger from the Sonic Boom sub-series resembles Aika from Skies of Arcadia, another Sega game. Both Sticks and Aika use a boomerang as their weapon of choice, have nearly identical hairstyles and have orange as one of the predominant colors in their design.

Andrew Rannells, the award-winning actor who played the lead character Elder Price in the play The Book of Mormon, was the voice director for the English dub of Sonic X. He played characters such as Bokkun, Decoe, Gamma, and Mr. Stewart. He also played the G.U.N. agents in the game Shadow The Hedgehog. Rannells actually worked on quite a few 4Kids shows during his time there, including Pokémon, Pokémon Chronicles, Kirby: Right Back At Ya!, F-Zero GP Legend, and voiced characters in 4Kids-acted games in the Yu-Gi-Oh and One Piece series.

Since Sonic was very popular in English speaking countries, one of Sonic's quirks in Japan (performed by Junichi Kanemaru) is that he may speak English at times, unlike other characters.

Tomoya Ohtani, a recurring composer for the series, frequently samples a portion of the famous drum break from the song Amen, Brother by The Winstons. This portion can be heard in 'Vs. Orcan' and 'Skullian' from Sonic Colors, the extra boss theme 'Boss - Big Swell' from Sonic Rush Adventure, and 'Cool Edge Day' from Sonic Unleashed, just to name a few.

Silver the Hedgehog was originally going to be an orange mink named Venice, but the developers decided against it and changed him into a hedgehog as they didn't think that a mink would fit in with the other characters.

At E3 2004, SEGA displayed a tech demo of Sonic the Hedgehog for the Nintendo DS simply named 'Sonic DS'. The game played by swiping back and forth on the bottom touch screen to allow Sonic to gain speed.

As a result of a sponsorship deal between the motor racing circuit Donington Park in Leicestershire, England and SEGA, the 1993 European Grand Prix was adorned with SEGA logos. Even the race itself was renamed the SEGA European Grand Prix.

Ayrton Senna won the rain-drenched event after passing four cars on the first lap and holding off his teammate Alain Prost through the race's length, and was presented a trophy which featured Sonic the Hedgehog. While the image of Senna holding this trophy was widely circulated around the Internet, it was unfortunately only a fake trophy used for a photo op. It's unknown what became of the Sonic trophy.

There was almost going to be a Sonic game based on skateboarding made for the Xbox, GameCube, and PlayStation 2 called Sonic Extreme (not to be confused with the cancelled Sega Saturn game of the same name). This game was developed by a San Diego company called Vision Scape Interactive.

Development began in 2003 shortly after Vision Scape finished up Bare Knuckled Grind. The game was initially planned to be ported to other consoles. There were also going to other skateboarding games using the same engine, but with different intellectual properties, including the Nickelodeon TV show Rocket Power. Unfortunately, budget issues is what resulted in all 13 projects cancelled. They later worked on cutscene animations for Sonic Heroes, and later pitched to Sega the Sonic Extreme prototype.

The prototype was finished in a week, and originally had planned to use hoverboards. The player would be to race against Sonic or Shadow. Yuji Naka, former head of SEGA, was impressed at the time and asked Vision Scape to make design documents for the game. However, when they did show the documents to SEGA, they went silent.

Later on, in September 2005, Sonic Riders was announced. People at Vision Scape believed that SEGA took some of the concept from Sonic Extreme. and used it for Sonic Runners. However, legal issues from SEGA forced Vision Scape to shut down in 2006.

In 2012, Ken Balough announced that Big the Cat would be retired from the franchise for the time being as they could not find a good use for the character, and all things that they already tried didn't work out for him. This however did not stop Big from making cameo appearances in Sonic & All-Stars Racing Transformed, having a trophy in the 3DS version of Super Smash Bros. 4, having a spirit in Super Smash Bros. Ultimate, being playable in the mobile games Sonic Runners and Sonic Forces: Speed Battle, and even making a full appearance in Lego Dimensions and Team Sonic Racing. Big was eventually reintroduced to the mainline Sonic games in Sonic Frontiers.

In an interview, Naoto Oshima was asked if the blue birds were a direct reference to the game Flicky. Oshima said yes, and also mentioned that he asked game's designer Yoji Ishii's permission to use Flickies in his work.

Before the singular story concept of Sonic fighting against Dr. Robotnik, Sonic's character development was very different. During the 2018 Game Developers Conference, game designer Hirokazu Yasuhara and character designer Naoto Ohshima revealed that the series almost had connections to World War II.

"Sonic" was originally going to be a fighter pilot who earned the nickname "hedgehog" because of how his hair stood up while flying his plane at high speeds, while the Sonic the Hedgehog design known today was merely a nose decal on the front of his plane. The details of his time in the war were then re-imagined as a children's picture book by the pilot's wife. She took the Sonic the Hedgehog design and based it on her war veteran husband, making the game a story within a story. American pilot Chuck Yeager, the first pilot to break the speed of sound, was also mentioned in Yasuhara and Ohshima's pitch summary.

Additionally, they showed off line art for a proposed dance sequence during the game, originally intending for Sonic to be a trendy dancer, but this along with the meta-story elements were scrapped during development.

In the third installment of the Untold History of Japanese Game Developers book series released in 2018, Ohshima reiterated that Sonic was going to be a human boy, but SEGA rejected the design, not wanting their mascot to be a human, and Ohshima admitted that he does not have any concept art of Sonic as a human due to his proposal just being a basic outline. Despite this rejection, the core layout of Sonic the Hedgehog's speed-based gameplay and map design was set in stone by this time.

The live-action Sonic the Hedgehog movie was originally slated to be released sometime in November 2019, but was delayed to February 14th, 2020 as a result of the reception to the film's debut trailer released on April 30th, 2019. The main cause of the backlash being that the film was planned to feature a humanoid redesign of Sonic that was so negatively received by fans and audiences alike that the film's team hired artist Tyson Hesse, who had previous experience with the Sonic franchise, to make a more visually appealing redesign for the final movie that was more positively received and incorporated into all previously-released film footage.

The title screens of Sonic the Hedgehog and Sonic the Hedgehog 2, with Sonic (a character known for his super speed) posing and waving his gloved hand inside of a ring lined with stars and a ribbon banner at the bottom, could possibly be taken from the logo of the 1981 anime adaptation of the Akira Toriyama manga "Dr. Slump" and its speedy protagonist Arale. It should also be noted that the ring surrounding Sonic has giant wings protruding from its sides, which appear to reference the angel wings on Arale's cap that also feature in the intros to the anime and some of the Dr. Slump films.

While it's not known if any Sega employees have commented on this connection, it was acknowledged in the form of a small cameo appearance where Sonic gets outrun by Arale in the 1993 sequel manga "The Brief Return of Dr. Slump".

Some of the names of the Arcade Shop missions in Lost Judgment which are unlocked through playing Sonic the Fighters are references to aspects of the Sonic franchise.

The missions for beating Sonic, Tails, Knuckles and Amy are all named after their themes from Sonic Adventure or Sonic Adventure 2: Live and Learn, Believe In Myself, Fighting Freak and My Sweet Passion.

The mission for beating Fang the Sniper is titled Knack For Trouble which could be a reference to both Fang's original Western name Nack the Weasel as well as his debut game Sonic the Hedgehog: Triple Trouble.

The mission for beating Bean the Dynamite is titled Mean Bean Machine after the 1993 Sonic-themed Western localization of Puyo Puyo, Dr. Robotnik's Mean Bean Machine. Ironically, Puyo Puyo did not appear in Lost Judgment despite being in it's predecessor, Judgment.

Finally, the mission for beating Espio is titled Chameleon Detective after Espio's role as a detective starting with Sonic Heroes. It could also be a nod to the Lost Judgment's protagonist Yagami being a detective who often needs to don disguises to blend into places.

Ryan Drummond (voice of Sonic the Hedgehog from 1999 to 2004) revealed that during Sega's recasting of the Sonic the Hedgehog cast in 2010, he had auditioned for the role and had actually won. However, Sega requested Drummond to leave his union, so Drummond ultimately declined the offer.

The appearance of Longclaw in Paramount’s Sonic the Hedgehog films is reminiscent of the tiles that resemble an owl's head in the Labyrinth Zone from the original Sonic the Hedgehog. In fact, the first film's opening scene features the tile design engraved on a rock as an Easter egg, further hinting at the connection.

The character of "Ugly Sonic" in the 2022 film Chip 'n Dale: Rescue Rangers is based on the infamous first design of Sonic the Hedgehog featured in the first trailer for his 2020 film. Voiced by Tim Robinson, Ugly Sonic acknowledges the mockery of appearance (especially his realistic humanoid teeth) and uses it to find new work.

According to the director Akiva Schaffer, the company that provided the effects for this film, MovingPictureCompany, also provided the CGI for the 2020 Sonic film, meaning for Ugly Sonic, they had to "repeat their mistakes on purpose this time."

Interestingly, Ugly Sonic wasn't originally planned to be in this cameo; Jar Jar Binks from Star Wars was initially meant to be featured as the character acknowledging his mockery.