From Laura Geggel at LiveScience:
“Because of the animal’s decomposition, it is difficult to be certain what this animal may have been,” John Hyde, a program leader of fisheries genetics at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center in La Jolla, California, told Live Science in an email. “However, it does resemble a black sea hare (Aplysia vaccaria) that are fairly common in this area.”
Sea hares, a group of sea slug species,fall within the class of gastropoda. If the strange animal were a black sea hare, that could explain its large size: A. vaccaria is the largest gastropod in the world — it can weigh as much as 30 lbs. (13.6 kg) and grow as long as 29 inches (75 cm), according to the Aquarium of the Pacific in Long Beach, California.
But not everyone is on board with this interpretation.More.
You have to see it here.
Most of the ocean is unknown. One wonders what would become of much dogma if we knew even twice what we know today.
See also: Cambrian explosion: “Tulip animal” had unique feeding system