Sonic Underground
Season 1, Episode 15: Sonic Tonic
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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.
All Episodes - Season 1
Episode 1
Beginnings (Origins, Part 1)
Episode 2
To Catch a Queen
Episode 3
Mobodoon
Episode 4
The Price of Freedom
Episode 5
Underground Masquerade
Episode 6
Tangled Webs
Episode 7
The Deepest Fear
Episode 8
Who Do You Think You Are
Episode 9
The Last Resort
Episode 10
Come Out Wherever You Are
Episode 11
Winner Fakes All
Episode 12
A Hedgehog's Home Is Her Castle
Episode 13
Artifact
Episode 14
Bug!
Episode 15
Sonic Tonic
Episode 16
Friend or Foe?
Episode 17
Head Games
Episode 18
When in Rome...
Episode 19
The Jewel of the Crown
Episode 20
Three Hedgehogs and a Baby
Episode 21
Dunes Day
Episode 22
Mummy Dearest
Episode 23
Hedgehog in the Iron Mask
Episode 24
Six Is a Crowd
Episode 25
Flying Fortress (Chaos Emerald Crisis, Part 1)
Episode 26
Wedding Bell Blues
Episode 27
No Hedgehog Is an Island (Chaos Emerald Crisis, Part 2)
Episode 28
Getting to Know You (Origins, Part 2)
Episode 29
New Echidna in Town (Chaos Emerald Crisis, Part 3)
Episode 30
Harmony or Something (Origins, Part 3)
Episode 31
Country Crisis
Episode 32
Haircraft in Space
Episode 33
Healer
Episode 34
Sonia's Choice
Episode 35
The Big Melt
Episode 36
Sleepers
Episode 37
Bartleby the Prisoner
Episode 38
The Art of Destruction
Episode 39
The Pendant
Episode 40
Virtual Danger