Adapted from a French cartoon called Sonic le Rebelle, Sonic Underground is the third SonicAnimated Adaptation made. It was produced by DIC Entertainment.Sonic and his two siblings, Sonia and Manic, are left by Queen Aleena as Doorstop Babies to families, each of a different class. Eventually, they meet together when grown up, and guided by the Oracle of Delphius, they set out to thwart Robotnik, find their mother, and form the Council of Four.Thanks to so many original characters and the omission of almost all the official characters existing at the time, despite there being potential room for them (Cyrus could easily have been Tails), and since many of the background characters were more alien than any Earth-based animal, many Sonic fans and even fans of the series debated whether it was really even intended to be a Sonic show, and that the characters of Sonic and Dr. Robotnik were just a hook for Sonic fans. Even the series plot is basically a This Is Your Premise on Drugs take of the Sonic vs. Robotnik story.Regardless of the characters used, it was most likely the "hook" for the show that resulted in its thorough panning. This was that the real premise of the show was that Robotnik had banned all music, and our three protagonists were Musical Assassins with The Power of Rock. Each episode's climax would inevitably be a song performed by the triplets, often with An Aesop based on the events of the episode.Not to be confused with the twootherwestern animated series based on Sonic the Hedgehog, the Anime series Sonic X, the OVASonic the Hedgehog: The Movie, or the game that helped to kill it off that same year, Sonic Adventure.Now on Disney XD and Netflix.After 10 years of being Cut Short, the story will conclude in the Archie Sonic Comic's Sonic Universe. Maybe.
Broken Aesop: The 21st episode involves a seller with one of the Queen's gems and willing to sell it at a high price. The trio doesn't have the money and Manic ruefully recommends 'acquiring it.' Sonia and Sonic are disgusted with Manic's thieving skills and shoot it down, even though they have stolen things before and Manic has taken things that saved their lives. Later Sonic's ingenious way of getting Sleet and Dingo out of their ship is to flood it with gallons upon gallons of unpaid for olive oil.
Canon Foreigner: Besides most of the main characters, a notable example is Cyrus, a lion and member of the resistance movement.
Canon Immigrant: Knuckles's grandfather, Athair, was a character from the Archie Sonic comics.
Catch Phrase: Much of Sonic's catch phrases from Adventures and SatAM were carried over, along with a few new ones, such as "Bummer mejores!".
Character Development: Yes, there actually was some. In the beginning, Sonia was pretty whiny, prone to complaining whenever her appearance was tarnished. Later in the series, she becomes more of a leader figure, and is easily the most focused of the siblings.
Death by Genre Savviness: In "Wedding Bell Blues," the hedgehogs know Robotnik's wedding to Queen Aleena is a trap, but fall into it anyway on the off-chance Aleena is actually there.
In another episode, in a call back to a Sonic Satam plot, Robotnik challenges Sonic to a race. Sonia and Manic, figuring Sonic couldn't resist, show up to try and rescue him...except he knew it was a trap and didn't show, and they have to be rescued.
Deus ex Machina: Queen Aleena made sporadic appearances to save the hedgehogs at times.
Disguised in Drag: Sonic and Manic have no qualms with dressing up as ladies to fool Robotnik and his goons.
Disappeared Dad: No mention has ever been made to Aleena's husband/the siblings' father. Not even in the Mirror Universe.
Dissonant Serenity: Early in the series, there was a strange problem with the animation where the characters would be smiling, even when talking about something depression or when something bad was happening. This was fixed as the series went on.
The Dog Bites Back: Happens twice within the same three-part episode. After Robotnik builds a Chaos Emerald-powered flying fortress, Sleet and Dingo grow concerned that they've outlived their usefulness, so they steal the Emerald and escape. Then Dingo, clearly tired of being slapped around by Sleet, steals the Emerald from him.
Failure Is the Only Option/ Cosmic Plaything: When Sleet and Dingo do their jobs of trying to capture Sonic, Sonia, and Manic, they fail. When the come up with plans that would mess up Robotnik... they still fail.
Feudal Future: Robotnik basically just extorts tribute from the aristocrats under threat of roboticization.
Forgotten Fallen Friend: The foster parents/educators of the hedgehogs were arrested and roboticized at the end of episode 1... and almost never thought or spoken of ever again in the show.
Halfway Plot Switch: Used, and nearly invoked, in "Wedding Bell Blues." Since Queen Aleena didn't show for her forced marriage to Robotnik, they'll instead crown Sonia queen in her stead.
Harsherin Hindsight: The scene the series ends on consists of the three hedgehogs remotely flying cargo aircraft into the side of a skyscraper...
Hoist By Their Own Petard: In episode 5, "Mobodoon", the gang tries to defend the town from Robotnik by using their musical instruments, but the musical number they performed earlier drained their power.
Hover Board: Manic's, though Sonic was shown with one in a single episode.
In Name Only: The only connections to the video games are Sonic, Dr. Robotnik, Knuckles, and the Chaos Emerald.
Identical Grandson: In "Mummy Dearest" the siblings find the tomb of a distant ancestor of theirs, who looks and acts just like Sonic.
Jerk with a Heart of Gold: Despite his wealthy lifestyle, cowardice, and the threats to his life should he turn his back on Robotnik, Bartleby has helped the hedgehogs at times.
In return, they broke him out of prison near the end of the series.
Kangaroo Court: One episode sees Bartleby being put on trial for aiding the resistance, with Robotnik as the judge, Sleet as the prosecutor, and for his defense attorney? Dingo. Of course the whole thing was a ruse to lure Sonia out...
Magic Pants: In the episode "Sonic Tonic" when the side effect of the titular tonic sets in, Sonia and Manic's feet grow huge but their footwear just stretches to fit and when their feet go back to normal so does their footwear. This is averted with Sleet and Dingo, however.
Mama Bear: Queen Aleena shot down some Swatbots to save Manic from being roboticized.
Meaningful Name: Sonia and Manic both make the word "Sonic" when "ia" and "ma" are removed from their respective names.
Myth Arc: Later episodes had more of a Story Arc, with the hedgehogs meeting Knuckles and Cyrus, and Bartleby joining the side of good.
Mythology Gag: In the first episode, we can see Uncle Chuck and Sonic in Uncle Chuck's base from Sonic the Hedgehog. When Robotnik is taking over, we can see a statue of King Acorn (also from SatAM) crumble.
Never Say "Die": Averted in the second episode when the trio fail a training exercise.
Sonic: "I got us killed."
Nice Job Breaking It, Hero: A lot of trouble could have been avoided if the Oracle hadn't told Robotnik about their plan to overthrow him.
Rich Suitor, Poor Suitor: Bartleby of the high class, haughty variety, and Cyrus, the street smart resistance member. Sonia's also shown affection for Knuckles, who doesn't really fit into either category.
Ridiculously Human Robots: While there are exceptions, such as Argus's roboticized form, most roboticized Mobians don't look much different from their regular selves. Some even look almost completely Mobian except for cybernetic eyes or limbs.
Robotnik also created a lifelike hedgehog baby as part of a plan to invade Sanctuary.
Unwilling Roboticization: Similar to how it works in Sonic SATAM, with one major difference being that most of the time, beings that undergo roboticization come out looking like cyborgs and not full-fledged robots. However, the minds of roboticized beings are still mentally enslaved to Robotnik and this control can only be broken temporarily.
Also, Robotnik used the roboticizer much more sparingly in this show, treating it more as a punishment for rebellion or failing to carry out his orders, rather than an umbralla treatment for all living creatures. Most people are not roboticized and Robotnik employs two unroboticized bounty hunters who are threatened several times with the treatment but are never actually subjected to it.