Acid Jazz Bass...
As for a finish... Gonna have a go at a Swirly Hydro Dip with these...
Neon Yellow, Neon Green, Neon Orange, Neon Pink!
I like the back, but if it's formed a skin, it's probably not worth trying to save. Good effort, though! 👍
Not as random as you were attempting, but I always thought the pendulum painting process could be very effective on a bass, especially given the contours of the body and non-regular outline. Something like this (apologies for the terrible music...):