Nibbles is the adopted pet cat of Starfire in the season three premiere, "Cat's Fancy". After Starfire saved Jump City from a bomb by hurling into space, but comes back to earth being unconscious in a crater, devastating Robin. When Robin trying to confess his true feelings to Starfire, she has regained consciousness and sees a white cat, which she adores the cat, adopts and calls him Nibbles. Back at Titans Tower, Starfire is happily playing with her new pet, which makes Robin really jealous, and he concludes that the only way to make Starfire love him is to make himself a cat. Raven, Cyborg and Beast Boy gloat about this and doubt his theory. The next morning, Robin believes that he turned into a cat which is actually a pair of cat gloves, to which Raven and the others laugh at him. Later, Robin dresses as a purple cat, much to Raven's surprise, Beast Boy and Cyborg. When Starfire comes out of the kitchen holding Nibbles and sees Robin in his cat disguise, she quickly tosses Nibbles out into the kitchen and adores Robin in his disguise, calling him "Sassypants". Nibbles was never seen throughout the rest of the episode nor the series. Cat's Fancy was his first and only current appearance in the series. Its possible that Nibbles still resides in the Titans Tower since Starfire tossed him back into the kitchen.
Nibbles is a normal feline white cat with transparent white fur who is fairly small in size, he has yellow eyes with medallion pupils and black eyelids, a pink nose and four black whiskers, two on each side of his face.