Insane in the membrane...

Ok, that's not completely accurate, as they're called chromataphores; pigmented cells possessed by squids (not exclusively), allowing their spectacular colour change. Each cells is lined with 16 muscles that contract and expand, revealing or hiding a specific colour. Here's what happens when a squid listens to Cyprus Hill!

Bear in mind squids do not possess ears. The sound in this case has been converted to an electrical signal and gently applied to the squid tissue. As cool and mind blowing as this is, I was saddened to hear the squid was not alive, this experiment involves dissected tissue. At least there's no further stress caused to the squid.

You can read more about it on it's ok to be smart

'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.'