Bioluminescent
Luciferin-driven chemical light production in dark depths for counter-illumination camouflage, glowing lures, and flashes.

Antarctic Krill
A crustacean about 6 centimeters long, so abundant it can turn the sea reddish-brown, that most larger Antarctic animals depend on, directly or indirectly.

Common Eastern Firefly
A beetle whose males trace a J of light at dusk and bleed defensive steroids when attacked.

Cookiecutter Shark
A shark up to 56 cm long that glows underneath to lure big animals close, then spins to cut a round plug out of them.

Gulper Eel (Pelican Eel)
A huge gape, a mouth that first unfolds and then inflates, and a glowing tail tip.

Humpback Anglerfish
The female wears a lure on her snout and can swallow a fish longer than herself.

Vampire Squid
Oxygen-poor twilight-zone living, pulsing blue arm tips, and an inside-out pineapple posture.