The Woods Hole squid goes nuts for Cypress Hill:
The specifics of what you're seeing:
The video is a view through an 8x microscope zoomed in on the dorsal side of the caudal fin of the squid. We used a suction electrode to stimulate the fin nerve. Chromatophores are pigmeted cells that come in 3 colors: Brown, Red, and Yellow. Each chromatophore is lined with up to 16 muscles that contract to reveal their color.