Klootonian

Klootonians are Marvin's alien species. A Klootonian has four eyeballs with two on it's antennae, five stomachs, three hearts, and three butts. Their hearing organs are located in the butt. They have blue skin and are very weak. Marvin was seen wearing a backpack so those have been invented by Klootonians. St. Glar Kai was maybe the only Klootonian who has it's own holiday, St. Glar Kai Day which it the Christmas version of Klootians. They greet eachother by slapping each other on the face. They sleep in pods as shown in Pilot. Their kidney looks like a liver. Their liver look like kidney. One of the stomachs are used for mating calls. The stomachs also have the ability to produce gaseous bubbles which allow them to levitate nearly freely. They can only come down by allowing the gas through his mouth, or burping. They can regurgitate substances ingested easily. They cannot pick up low sounds such as whispering. They also shown to be able to change the temperature of their finger from extremely hot to freezing cold. They can communicate with animals. They drink with one nostril and regurgitate it out with the other nostril.

It's revealed in Toothache that when they develop a toothache, you must pick the nerves out in a certain order, or else it would explode in half an hour. It explodes into fireworks.

They also come with an alien parenting guide attched to their foot, revealed in Pilot.