Cosmo, the Spacedog, is a recurring character in the Guardians of the Galaxy film trilogy in the Marvel Cinematic Universe. She is a dog that was sent to space by Soviets as part of an experiment, and ended up being captured by The Collector, a man who collects exotic lifeforms through the galaxy, and put in his personal museum. After the Battle of Earth, Cosmo remained on Knowhere to rebuild it, and later joined the Guardians of the Galaxy.
She was portrayed by Fred the Dog in Guardians of the Galaxy and was replaced by Slate starting from The Guardians of the Galaxy Holiday Special. Since her first speaking role in the Holiday Special, she is voiced by Maria Bakalova.