Bat-Thing is a character owned by both Marvel Comics and DC Comics, published as part of the combined Amalgam Comics one-shots by DC Comics in 1997. The character combines elements of Man-Bat of DC Comics and Man-Thing of Marvel Comics.
Dr. Kurt Sallis was attempting to splice genes by conducting genetic experiments on himself at a remote laboratory in a swamp outside of New Gotham City. The result transformed him into a Bat-like creature known as the Bat-Thing, and was despised for his appearance, much like Frankenstein's Monster.
The plot of the actual comic appears to be a mixture of a Crime Thriller and Horror. Inspector Bullock of New Gotham Police is examining a murder on a local drug-dealer who has been savagely clawed to death. All fingers appear to point to the Bat-Thing, until news arrives of an escaped convict, known simply as "Fat Freddy", who has a vendetta against Inspector Bullock and plans to claim his revenge by attacking the Sallis family who are under his protection.
However, the New Gotham Police discover that Bat-Thing was not responsible for the murder of the drug-dealer, but a victim of Fat Freddy who was attempting to cover his tracks. The Bat-Thing, despite suffering gunshot wounds by Bullock, defeats Fat Freddy and keeps his family safe, before returning to his laboratory in the swamp.