Cheat Code for Everlasting Bullet Bill in Mario Kart? Doesn't Exist

No such cheat code exists in any Mario Kart game.

Why

• Mario Kart uses deterministic item RNG (based on position, distance, RNG seed). No "infinite item" codes in retail code.
• Action Replay / Gecko codes for Mario Kart Wii / MK7 / MK8 / MK8 Deluxe exist for: Infinite Items (hold item), Item Modifier (force next box), Star Power always — but **not** a persistent Bullet Bill.
• Bullet Bill is a transformation state with fixed duration (~7-10 sec). Extending it requires ASM hacking, not a simple cheat.

Legitimate "Bullet Bill" Strategy

• Stay in **12th/11th/10th** place entering item box zones.
• Use **Mushroom/Star** to catch up *after* Bullet Bill ends.
• Online: Bullet Bill is nerfed (shorter, less steering) vs. offline.

Practice recovery driving; the item is a catch-up mechanic, not a win button.