Muggles' Guide to Harry Potter/Magic/Bat Bogey Hex

Overview
The Bat-Bogey Hex apparently causes the victim to be attacked by large, bat-winged bogies.

Extended Description
While the effect of this spell is never completely defined, we do see or hear of its being used a few times. This is one of Ginny Weasley's specialties, almost a signature spell; she uses it on Draco Malfoy to escape from the Inquisitorial Squad when she is being held captive in Dolores Umbridge's office in Harry Potter and the Order of the Phoenix, and it is her use of this spell on another student in the Hogwarts Express in Harry Potter and the Half-Blood Prince that brings her to the attention of Professor Slughorn.