The following contains spoilers for Sonic the Hedgehog 2, now playing in theaters.
One of the things that sets Sonic the Hedgehog apart from other video game characters is his expansive cast of colorful supporting characters. Over the years, the Blue Blur has met a variety of anthropomorphic animals with their own talents, allegiances and motivations. Sonic the Hedgehog 2 highlighted the introduction of two of Sonic's best known allies: the high-flying fox Miles "Tails" Prower and the stoic warrior Knuckles the Echidna. It also teased the arrival of another character who should be familiar to fans of the games.
In Sonic the Hedgehog 2's mid-credits sequence, the agents of the paramilitary Guardian Units of Nations (or G.U.N.) clear out the mess left by Team Sonic in their battle with Dr. Ivo "Eggman" Robotnik. The villainous doctor himself hasn't been found, but his sycophantic minion, Agent Stone, is discretely hiding among the soldiers. He overhears a conversation between Commander Walters, the leader of G.U.N., and one of his agents. The agent says that while G.U.N. was deleting any history of their partnership with Robotnik, they discovered a secret file, containing information on 50-year-old black site that contained experimental material. Walters recognizes this as "Project: Shadow," while somewhere else, a black and red hedgehog similar to Sonic opens his eyes.
Sonic fans will no doubt recognize this as Shadow the Hedgehog, a longtime antagonist in the games. Debuting in 2001's Sonic Adventure 2, Shadow was introduced as a rival to the Blue Blur. Though he was intended to only be a one-off character, Shadow proved popular with fans and returned as a playable character in 2003's Sonic Heroes and even headlined his own game in 2005's Shadow the Hedgehog, which introduced new mechanics to the Sonic canon.
In the games, Shadow was created in a lab by Dr. Gerald Robotnik, Eggman's grandfather, in an attempt to create an immortal "Ultimate Life Form" while trying to find a cure for his granddaughter Maria's terminal illness. Shadow and Maria form a bond, but it's cut short when G.U.N. shuts the project down, raiding the elder Robotnik's lab and killing Maria in the process. Maria asks Shadow to promise to protect the world, but after 50 years in suspended animation, he misremembers it. When he's revived by Maria's cousin Eggman in the present, Shadow decides to help him conquer the world so the hedgehog can get revenge on humanity.
Shadow's appearance in Sonic the Hedgehog 2 is just one of many easter eggs and references to the games that director Jeff Fowler and his team included in the film. "[A]s we were sort of setting out to plot [the Sonic 2 movie]," he said, "I think we all got excited to pull in that great imagery that all of the fans are going to get excited about when they see it on the big screen and create a cinematic version of the stuff that fans have loved from [the games]. It's a great problem to have that there's so many great Easter eggs that we can incorporate... I couldn't even begin to list them because there's so much stuff for fans to get excited about."
With Paramount having greenlit Sonic the Hedgehog 3 (as well as a TV spin-off focusing on Knuckles' continued adventures), fans can likely expect to see Shadow race onto the big screen sooner rather than later. Producer Toby Ascher said in an interview that "We’re creating a Sonic cinematic universe, so we knew we were going to add characters, like Tails and Knuckles; new to the films but beloved by gamers all over the world." The studio hasn't yet confirmed Fowler's return as director, but Fowler himself said, "Nothing would make me happier [than to direct Sonic 3.]"
Sonic the Hedgehog 2 is currently playing in theaters.
