Season 1 Episode
- Season 1 Beginnings (Origins, Part 1)
- Season 1 To Catch a Queen
- Season 1 Mobodoon
- Season 1 The Price of Freedom
- Season 1 Underground Masquerade
- Season 1 Tangled Webs
- Season 1 The Deepest Fear
- Season 1 Who Do You Think You Are
- Season 1 The Last Resort
- Season 1 Come Out Wherever You Are
- Season 1 Winner Fakes All
- Season 1 A Hedgehog's Home Is Her Castle
- Season 1 Artifact
- Season 1 Bug!
- Season 1 Sonic Tonic
- Season 1 Friend or Foe?
- Season 1 Head Games
- Season 1 When in Rome...
- Season 1 The Jewel of the Crown
- Season 1 Three Hedgehogs and a Baby
- Season 1 Dunes Day
- Season 1 Mummy Dearest
- Season 1 Hedgehog in the Iron Mask
- Season 1 Six Is a Crowd
- Season 1 Flying Fortress (Chaos Emerald Crisis, Part 1)
- Season 1 Wedding Bell Blues
- Season 1 No Hedgehog Is an Island (Chaos Emerald Crisis, Part 2)
- Season 1 Getting to Know You (Origins, Part 2)
- Season 1 New Echidna in Town (Chaos Emerald Crisis, Part 3)
- Season 1 Harmony or Something (Origins, Part 3)
- Season 1 Country Crisis
- Season 1 Haircraft in Space
- Season 1 Healer
- Season 1 Sonia's Choice
- Season 1 The Big Melt
- Season 1 Sleepers
- Season 1 Bartleby the Prisoner
- Season 1 The Art of Destruction
- Season 1 The Pendant
- Season 1 Virtual Danger
Sonic Underground - Season 1 Episode 15 Sonic Tonic
6.90 25 minutes A speed enhancing fluid deemed Sonic Tonic is created by Robotnik to make him as fast as Sonic so that he may finally catch him. Robinik's plan is successful and Sonic is captured, yet when Dingo begins to feel the side effects of the tonic, Sonic is able to make a run for it with a vial of the tonic in tow. Unaware of the side effects of the tonic, Manic and Sonia, envious of Sonic's speed, decide to use the tonic on themselves.
