Penny: Keep Your Head Up is a short comic giving a glimpse into Penny's private life. It is on Dark Horse Comics Myspace page, in issue number 23. Summary This is another comic book written by Zack Whedon for Dark Horse comics featuring a character from Dr. Horrible's sing along blog. The comic partially explains part of Penny's personal life and gives some explanation as to why she is still single. Special Appearances Dr. Horrible - Appears briefly getting beaten up in the park Capt. Hammer - Appears In the same shot beating up Dr. Horrible Wingspan - Appears fighting a giant robot