Man-Bat in Lego Batman: The video game
Man-Bat is the reverse of Batman: he is a bat-human hybrid. Robert Kirkland "Kirk" Langstrom was a bat biologist. He developed a serum that would give humans bat-sonar. He tested it on himself. It worked with a side-effect: he turned into a bat-human hybrid with super strength, hearing and vision with the intelligence of a bat. Batman cure him. Much later, Robert (not have learning his lesson) drank the serum again, but this time got this wife, Francine, to drink it too! She become the "She-Bat". They go on a ramage until Batman cures them. Robert and Francine had a daughter and a bat-like son. 1 year after the Infinite Crisis, Talia al Ghul got the serum from Francine and turned the League of Assassins into man-bats. After Batman's death, Robert (in human form) had nigthmares of killing Francine as Man-Bat. His wife disappears, so Robert left with the serum. After being kidnapped by the "Picth Fever"-like Doctor Phosphorus, Robert learns he no longer needs the serum to transform into Man-Bat and Doctor Phosphorus has his wife. So Robert turned into Man-Bat to save his wife.