Nemo

Nemo Frensky is Francine Frensky's pet cat. he is main antagonist in some Arthur episodes. He was first introduced in the Season 3 episode Francine and the Feline, being discovered by Oliver Frensky in an Elwood City Dump landfill in which he worked which led to the adoption of Nemo. Initially, Catherine had adopted him as her own pet, naming him Rose Petal, but later, she realized that he was more suitable as Francine's pet, leading him to be renamed Nemo. His biological parenthood is unknown.

Like Pal, in some episodes he is shown to be able to communicate with other pets, human babies, and toys. He is usually cast as an antagonist in these situations. During these interactions, especially with Pal, he is prone to insults and sarcasm, but can occasionally be helpful.

Trivia

 * Nemo's appearance has changed since his debut. He had a much "fuller" feline face at first, but in later appearances does not have much of a muzzle.
 * Nemo was friends with Pal in Francine and the Feline, but they have since become mortal enemies. One exception is in the episode, "Pet Projects," when their owners and friends were putting embarrassment in the camera films starring them. They formed an alliance to get revenge after the humans did the films for their own sake.
 * On the front cover of Arthur's Pet Follies on VHS and DVD, Nemo's original design was used.
 * Nemo often calls Pal "dog" or "puppy".
 * According to Francine in the episode "What is that Thing?", Nemo was named after "Captain Nemo" from the Jules Vernes novel Twenty Thousand Leagues Under the Sea.
 * Nemo is allergic to milk, as seen in "Pet Peeved."
 * Since Nemo was found in the city dump it could be possible that he is a feral cat.