The story
From bloody + belly + comb jelly, named due to this animal's colour.
Etymology from Wiktionary, CC BY-SA 4.0.
bloodybelly comb jelly
Today it means: A species of mesopelagic ctenophore, Lampocteis cruentiventer, found at a depth of 250-1,500 meters deep in the North Pacific Ocean, ranging in color from deep red, purple, or black to pale purple. Full definition →