Katarina "Kat" Cassidy is a young girl and school student who is the only one who can speak Kenny's language. She is obsessed with sharks. She is Kenny's owner and best friend. She is optimistic and fun loving. She possesses rather unrealistic characteristics. She usually wears sandals like her parents, but later in the series she wears tennis shoes. She is biracial (half white and half Asian). In the episode "I Love the Nightlife", it has been revealed that her full name was Katarina. She is 10 years old, but in "Goodbye, Old Chum", she turns 11.