Kuro

Kuro is a black cat with huge ears which follows Kanako. It first appears in book 11 in the manga, and in the Love Hina Again OVA. It becomes friends with Tama-chan. Kaolla is very interested in researching it and Sarah calls him "witch cat" after knowing about Kuro's unusual abilities to fly (using its oversized ears) and talk. In the anime, Kuro can talk, but in the manga, instead of Kuro being able to talk, it is just Kanako's ventriloquism. It carries a bell on its tail, which sounds as characteristic when Kanako appears.

Source: Wikipedia.