In a 1999 interview with the game's producer Yuji Naka, character designer Sachiko Kawamura and main planner Takafumi Kaya, published in the Dreamcast Magazine vol. 35, Kawamura stated that there were several early ideas going around to pair up two different animals in a "cat-and-mouse" dynamic of "things to chase, and things that do the chasing". Pairings such as elephants chasing ants, lions chasing deer, and aliens chasing humans were suggested among others, but they eventually came to the conclusion that the most intuitive way to communicate this concept was through cats chasing mice in the first place.