Why would a bat sting when hitting?

Bats do not sting; they are flying mammals and lack stingers. If you are referring to the "sting" sensation when a bat hits, it may be due to the bat's speed and the impact of its solid body or wings, which can cause a painful or surprising contact. Additionally, if a bat is frightened or feels threatened, it may react aggressively, potentially leading to a painful encounter. However, their primary defense mechanism is echolocation and flight, rather than physical aggression.