Mooncalf

"They seemed monsters of mere fatness, clumsy and overwhelmed to a degree that would make a Smithfield ox seem a model of agility. Their busy, writhing, chewing mouths, and eyes closed, together with the appetizing sound of their munching, made up an effect of animal enjoyment that was singularly stimulating to our empty frames."

- Bedford describing his first impression of the mooncalves in The First Men in the Moon

The Mooncalves are a species of non-sapient herbivores native to the Earth's moon. These elongated, caterpillar-like creatures are bred as livestock by the native Selenites. Their impressive length is estimated at almost two hundred feet, with an approximated four feet body width and a leathery white skin with a black strip running on the back. Also present are numerous extremely short legs and a low head with eyes that are kept shut when the organisms are out in daylight. They are voracious grazers who survive underground along with their insectoid masters during the two weeks long night, migrating to the surface on the dawn of the equally long days when the native plants start to germinate at impressive speed, turning desert into jungle in a matter of hours.

Trivia

 * Despite their invertebrate appearance, the skeleton of a dead mooncalf is featured in the 1964 movie adaptation of The First Men in the Moon