In the latest edition of Sunset TV, Brandon Winfrey went through questions from the community, one being about what kind of stuff didn't make it into Sunset Overdrive. They then showed off a prototype boss that never made it into the final game that Insomniac Games was kicking around early on.

This was a tentacle boss that sprouted from a bus. An interesting idea to say the least, especially considering how great the bosses were in Sunset Overdrive, as few as there were. Brandon also revealed that Sunset Overdrive was in development for three years with one of those years being pre-production.

https://www.anrdoezrs.net/links/3607085/type/dlg/sid/UUhgUeUpU47189/https://www.youtube.com/watch?v=DB_2rOfMkuE