Man-Bat

He first appeared in Detective Comics #400 (June 1970) and was created by Frank Robbins and Neal Adams. Dr. Kirk Langstrom, a scientist specializing in the study of bats, develops an extract intended to give humans a bat's sonar sense and tests the formula on himself because he is becoming deaf. The extract works, but 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.

Done in MS Paint.