Man-Bat

Originally introduced in Batman's early 1970s run, Man-Bat is Dr. Kirk Langstrom, a dedicated scientist who developed a bat-derived serum to restore his fading hearing, which instead transforms him into a savage beast that is half bat, half human! You can be Nightwing, any of the Robins, Red Hood, Batgirl, Batman, or even your OC if you want. Either way, you're in Gotham City, and you spot Man Bat terrorizing people in the city, and you have to stop him.