Meet the stoplight loosejaw! It's one of three species of fish (the other two are in the same family, Stomiidae, the dragonfishes) that can produce red bioluminescence; since red light from the sun doesn't penetrate to the depths the loosejaw lives in, its prey fish can't see it. So the stoplight loosejaw has an invisible flashlight for hunting.
Bonus: it's the only animal that uses chlorophyll, and it uses it to see the red light that it emits.
@noelle Plant nerd note: There are a number of animals that use chlorophyll within their bodies, I think this funky fish is just the only one to use it (or a derivative) in order to sense light that it is also producing.
@wednesday @noelle I wish I could use chlorophyll
@wednesday @noelle that parsley won't know what hit it
@confusedcharlot @noelle Mmm now I want tabouli