Something very large of its kind.
Any species of the extinct genus Mammuthus, of large, usually hairy, elephant-like mammals with long curved tusks and an inclined back, which became extinct with the last retreat of ice age glaciers during the late Pleistocene period, and are known from fossils, frozen carcasses, and Paleolithic cave paintings found in North America and Eurasia.
Comparable to a mammoth in its size; very large, huge, gigantic.
Any huge marine animal.
A large and aggressive creature living in or under the sea that attacks ships.