Rara is a gigantic flying squirrel (About the size of a dog) which the boy, Usabu Kentaro, considered "as his pet and his friend".
Shiroi Senshi Yamato
Rara lived in the forest and being still relatively small, it robbed food from a near village of puppies. When Rara grew the increasingly big threat and danger began to develop gradually from it to everybody. Usabu Kentaro killed it before the squirrel lost its temper and started to kill all of them.
See more pictures in Rara (SSY)/Gallery