Trope-a-Day: Bioluminescence Is Cool

Bioluminescence Is Cool: And available in several varieties from your local bodysculpt clinic, along with some interesting variations on the theme of chromatophores.  Ah, fashion industry, what will you bring us next?

Also used for some more practical purposes, like non-electrically dependent emergency lighting, engineered glowing trees for streetlights, detectors of this and that, etc., etc.