!!! I just had some ideas sythesize into a more interesting way to make the effect of bioluminescent tentacles without it looking so much like LED colors.
Shine a bright UV led (365nm maybe? Shorter?) through a strand of thick side-glow optical fiber, maybe clad in an extra layer or two of clear tubing so the flexibility behaves nicer. On the end, put on a small bead of casting resin filled with phosphorescent pigment.
@starkatt . . . was that wordplay intentional? grin
@ElectricKeet no but I'll take it.