Scientist Kirk Langstrom worked as a Zoologist at the Gotham City Zoo, and experimented with bat mutagen to create a serum to replicate the creatures' long life under the tutelage of his father-in-law, Dr. Marsh. Dr. Marsh was obsessed with the idea that humanity would not be able to survive mass extinction, whereas bats would, and devleoped a serum that would give people bat-like abilities to survive. However, Dr. Marsh was unwilling to test the serum, whereas his son-in-law Dr. Langstrom was. After he tested the serum on himself, Langstrom became the vicious Man-Bat. Though Batman eventually cured Langstrom, the creature made future appearances.