User blog comment:Mobo85/"Phineas and Ferb: Mission Marvel" Debuts August 16/@comment-1896159-20130628214646/@comment-1896159-20130628235845

I found one article that mentioned Dan & Swampy were already thinking of a second marvel special. It also mentioned perhaps the potential for a spoof off of the "Star Wars" franchise as well. If I find the article again I'll post the link.