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| Series | Sonic Underground (DiC, 1999) |
| Season | Season 1 (the only season) |
| Episode | Episode 16 of 40 (production order) · production no. 416 · WildBrain no. 116 |
| French title | L’île d’émeraude |
| First aired (France) | 28 February 1999 · TF1 |
| First aired (US) | 20 September 1999 · BKN Kids II (syndication) · 16th in US broadcast order |
| Written by | Kevin Donahue |
| Directed by | Marc Boreal, François Hemmen and Daniel Sarriet; Tom Smith (US) |
| Song | “Not Always What They Seem” |
| Previous episode | Sonic Tonic (S01E15) |
| Next episode | Head Games (S01E17) |
KnucklesThe Floating IslandChaos Emerald
Friend or Foe? is episode 16 of Sonic Underground, DiC’s 1999 cartoon about Sonic, Sonia and Manic, the hedgehog triplets of Queen Aleena. It is number 16 in production order – the order TF1 first showed the series in France, where it premiered on 28 February 1999 – and it was the 16th episode to air in the United States, on 20 September 1999. It was written by Kevin Donahue, and its song is “Not Always What They Seem”.
Synopsis
Following a lead on their mother, the siblings travel to the Floating Island, which is held in the sky by a Chaos Emerald. Sleet and Dingo are after the same gem, and they reach the island’s guardian first.
Knuckles is a proud echidna who has filled his home with traps, and the villains have told him that the hedgehogs are thieves coming for the Emerald. He jumps to conclusions and takes on Sonic, and while the two of them brawl, Sleet and Dingo go for the prize.
Knuckles works out in time who the real thieves are, the hedgehogs convince him that they mean his island no harm, and together they protect the Emerald. It is the start of a wary friendship that matters a great deal later in the series.
The Song: “Not Always What They Seem”
“Not Always What They Seem” is a warning about first impressions, for a hothead who has been lied to about his visitors.
Key Moments
- Knuckles makes his Sonic Underground debut.
- Sleet and Dingo turn Knuckles against the hedgehogs.
- Sonic and Knuckles team up to protect the Chaos Emerald.
Trivia
- As in Sonic the Hedgehog 3, Knuckles is a lonely island guardian tricked into seeing Sonic as a thief.
- Knuckles is voiced by Brian Drummond.
- Knuckles and the Emerald return in the three-part story that starts with Flying Fortress.
Watch the Episode
The full episode, uploaded by WildBrain’s official Sonic The Hedgehog – WildBrain YouTube channel (checked 6 November 2026).
Part of our Sonic Underground episode guide. The series page covers the characters, the songs, the prophecy and the show’s history.
Sources: titles, writers, songs and air dates from Luke’s original Sonic Scene guide, cross-checked with Wikipedia, Sonic Wiki Zone and Sonic Retro (Wayback copy); synopsis written for Sonic Scene from the episode, its official description and several fan references; title card and screenshots via Sonic Wiki Zone, copied to our media library.