Marine Dylanus

Marine dylanus is a whale-like manatee-like descendants of feral dylanuses of 10 million years from now that adapted to life as a fully-aquatic mammal. Despite cetaceans, pinnipeds, and manatees still around, marine dylanuses still flourish as marine dylanuses mainly feed on, not just schooling fish, crustaceans, or cephalopods, but also jellyfish (as they are immune to the jellyfish's stings), common seastars, eels, seahorses (due to strong jaws and teeth to allow them to crush seahorses and eat them), stonefish (as they're immune to stonefish venom), lionfish (as they're immune to lionfish venom), stingrays (as they learn to remove the ray's barbs with stones and/or coral), and seaweed.