K.K. Slider Not in Animal Crossing: Wild World (GameCube)

K.K. Slider debuted in Animal Crossing: City Folk (Wii, 2008). He does not appear in Wild World (DS, 2005) — and Wild World was never on GameCube.

Wild World Music

• Radio in house plays hourly K.K. songs (instrumental)
• No live performances, no requests, no guitar
• Soundtrack accessible via Town Hall bulletin board → "Town Tunes"

First K.K. Appearances

• Animal Crossing (GCN, 2001): Saturday nights at train station — but this is the GameCube original, not Wild World
• Wild World (DS): Radio only
• City Folk (Wii): Saturday nights at bus stop — first with requests
• New Leaf (3DS): Club LOL, DJ K.K.
• New Horizons (Switch): Resident Services plaza, full band

You may be conflating the GameCube original (2001) with Wild World (DS, 2005).