Assistant: Hobby had two different definitions in The Death Note:
1. Hobby the Shinigami: He is a Shinigami that resembles a teddy bear. His name was written in Light Yagami's Death Note when he accidentally dropped it in the human world, effectively killing him and extending Light's lifespan by another month or so.
2. The nickname Rem gave Misa: Due to her interest and fondness to modeling and becoming an idol.