Obviously, I could describe some crazy sci-fi bass with alien technology and able to morph into whatever form factor I want instantly (from upright to electric short scale!), but that's just way too unrealistic (though fun to imagine). So, more realistically, I would describe something that's probably doable with current technology: Can transform from fretted to fretless (this tech already exists) instantly. Very flexible pickup system (like the Sims Super-Quad system) that can achieve any existing tone, but with the addition of the ability to slide the pickups to different positions on the body for maximum flexibility. Very flexible onboard EQ with 4-bands and sweepable frequencies for all four bands, and the frequencies are labeled (or shown as tiny LED display somewhere on the bass). One master volume, and then the blend/switches for the Super-Quad pickups system. Awesome piezo pickups that can sound very close to upright and acoustic. Neck that's never affected by weather/humidity and never needs to be re-setup once you dial in the ideal setting. Tung oil/satin type of finish that's comfortable to the touch, but will never get buffed to become shiny by your hands. Great clarity on the B-string but not multi-scale. Prefer 34" scale. Automatic tuning that doesn't require you to pluck the strings and is almost instant. Very fast and comfortable neck with low-action and fret buzz. No neck-dive and very light weight body (but not too light that it wouldn't stay put when you move around). Maybe 6.5 lbs. is about perfect. Headless so there's no headstock/tuners to bump into stuff. Ergonomic like the Torzal twisted necks, with tapered body edge for the forearm to rest against. LED fret markings with customizable colors. Digital finish (like on some concept cars) that can display any color/pattern/texture you want, but in very high resolution so it's indistinguishable from reality (other than the specularity of the material) This one is admittedly the most sci-fi one, so it's very unlikely.