Cetacean Anatomy – The character has the form and/or characteristics of a cetacean. Cetaceans include whales and dolphins. Cetacean Anatomy is also known as Cetacean Body, Cetacean Form, Cetacean Manifestation, Cetacean Mimicry, and Cetacean Physiology. Subcategory of (268) Mammalian Anatomy.
Giganto (Marvel) is more or less a whale that can walk (Marvel Pets Handbook #01).
Orca (DC) had Orca DNA inserted into her make up as part of a gene therapy treatment (Batman #579).
Razorfin Dolphin – Creature Collection II. Dark Menagerie
Armoured Gideon II – 2000 AD #828
Whale – TSR 2140A Monstrous Manual