course Flutterbat is more like one of Batman's villains Man-Bat:
Dr. Kirk Langstrum created a serum that hopefully would give a human a bat's sonar abilities, he hoped it would cure him being deaf. It worked too well as he transformed into a half human half bat monster known as Man-Bat! Batman would have to fight him several times & capture to cure him.
Sooo, Saddle Rager gets turned into a Vampire, and begins a new secret-hero career as the mysterious Batmare, whilst the rest of the Power Ponies wonder where SR keeps disappearing off to, and who this new hero is. IDEAAAAA!