Hawaiian Bobtail Squid; Euprymna scolopes

Bioluminescence can be a very helpful evolutionary feature for creatures who live in the deep ocean where sun-produced-light is scarce. The Hawaiian bobtail squid doesn’t bioluminesce itself, but rather it hosts colonies of bioluminescent Vibrio fischeri bacterium in a mutualistic relationship.

Image via animalword

Cute, brightly colored, and it glows!