Bromosaur

The Bromosaurs are massive aquatic extraterrestrials that resemble a cross between a whale and a crustacean. They're bottom feeders who are mostly harmless unless if one were to try and remove a parasitic cortex jellyfish that latches onto their blowholes which pumps out pure water. The Bromosaurs' sex can also be defined by whether or not they have a cortex jellyfish with males more likely to have a cortex jellyfish than females.