James Gunn has already confirmed Nathan Fillion would have a “very small fun cameo he did as a favor to me” in Guardians of the Galaxy, but he kiboshed the rumor that Fillion would be playing Nova. So who is he playing?
Consider everything below to be a spoiler. Or completely inaccurate. Could go either way.
Schmoes Know claims to have a source with knowledge of Fillion’s cameo. He’s rumored to be voicing another talking animal almost as awesome as Rocket Raccoon, the telepathic dog Cosmo who is also a cosmonaut because this part of the Marvel universe is ridiculous.
Cosmo is a telepathic Russian dog in the Marvel Comics universe. The character was created by Dan Abnett and Andy Lanning, first appeared in Nova vol. 4 #7. Within the context of the stories, Cosmo is the security chief of the spacestation Knowhere and a member of the Guardians of the Galaxy.
Here are a few panels of Cosmo, for reference.
As much as I’d love Cosmo to be in Guardians of the Galaxy, I’m not so sure. Yes, Knowhere is definitely in the movie, but would fans recognize Nathan Fillion’s voice if he were doing a Russian accent? And what of this seeming denial posted by James Gunn?
On the other hand, talking cosmonaut dog saying, “The hammer is my red rocket”. Let’s do this.