The creature called Man-Bat escapes Arkham Asylum with a secret weapon and a sonar shriek that makes citizens turn batty, and it is up to Batman to keep Gotham City from becoming a city of bats. The creature called Man-Bat escapes Arkham Asylum with a secret weapon: a sonar shriek that makes citizens turn "batty." Can Batman keep Gotham City from becoming a "City of Bats"? Book #2