Sergei Alexander Bobinsky (Russian: Сергей Александр Бобинский, Sergey Aleksandr Bobinskiy), otherwise known as Mr. B or as he prefers it Mr. Bobinsky, is a major character of . He is Coraline Jones's Russian neighbor who lives in the upstairs flat of the Pink Palace Apartments in the stop-motion film, Coraline
He owns a jumping mice circus. Coraline assumes he is crazy and Mel Jones believes that he's a drunk.