Lord Nibbler of the planet Eternium is a fictional character from the animated series Futurama. He is a member of a very cute and adorable race with voracious appetites who are extremely long-lived (having lifespans of thousands of years).
"Nibbler" is only the cutely ironic nickname that his human companions have given him, ironic because he is capable of swallowing animals whole that are several times his own size. His real name is never given, because as he once said, "in the time it would take to pronounce one letter of my true name, a trillion cosmoses would flare into existence and sink into eternal night."
Throughout most of the series he appeared to be a semi-intelligent being who made simple animal sounds of chattering or warbling, would purr like a cat when his fur was stroked, and had a litter box for pooping. His feces are made of dark matter, "each pound of which weighs over ten thousand pounds," and was originally able to power space ship engines, although later on dark matter was rendered inert and could no longer be used as such. It is unknown if Nibbler is actually not potty-trained or if he simply prefers pooping in his diapers.
Later in the series, he revealed himself to be the extremely hyper-intelligent alien that he is, and when he desires to do so, can communicate with his human companions in a very deep, booming and well-modulated voice.
It was Nibbler who had the main protagonist, Philip J. Fry, cryogenically frozen so that he would be present in the 31st century because Fry was the only being in the universe capable of defeating a race of hyper-intelligent brains who were going to destroy the universe.
His race is called the Nibblonians by his human companions, and he and his kind also refer to themselves as such for the sake of convenience. The Nibblonians are the oldest race in the universe; at the time of the Big Bang they were already 17 years old.
In the episode from which these screen captures were taken, Nibbler discovers that the cats of Earth are actually a race of intelligent aliens who are going to destroy the Earth in order to save their own planet. He and his human companions succeed in foiling the cats' plan, although after they save the Earth they discover that the planet now rotates opposite from its original rotation, meaning that the sun would be rising in the west. This, they decide, is "close enough."
In the last picture above we see that Nibbler's pipe allows him to retain a quiet dignity even while having his diaper changed.