Roppuru

Roppuru, otherwise known as Loppic or Roppel is a boy who appears in the 1981 film, Doraemon: The Record of Nobita: Spaceblazer and its 2009 remake, The New Record of Nobita: Spaceblazer. He lives on the planet Koya Koya. A portal to his spaceship opened in Nobita's room during a time warp. He became friends with Nobita and Doraemon who helped him save his planet. He has an alien-type rabbit friend called Chammy.

(Source: Doraemon Wiki)