Professor Langstrom, Manbat

Working on characters from Batman again, heres Professor Kirk Langstrom: alias: Manbat. a scientist specializing in the study of bats,tits develops an extract intended to give humans a bat's sonar sense and tests the formula on himself because he is becoming deaf. While it works, it has a horrible side effect: it transforms him into a hideous man-sized bat.
The serum also takes away his intelligence, so he goes on a mad rampage until Batman can find a way to reverse the effects.