Ted Sieger's Molly Monster - Der Kinofilm

Molly Monster is the deeply-loved only-monster of Popo and Etna Monster. She spends her days in familiar surroundings playing with her best friend Edison, a clockwork toy with a life of his own. But when Mama gives birth to an egg (which Papa must hatch) Molly sets out on a journey to find her new place in the family. The journey takes her far away from home and over the Wild Hills to Egg Island, where she is reunited with her Mama and her Papa, and her new mini-monster sibling. (imdb)