Bat-Bogey Hex
incantation unknown
Engorges an opponent's 'bogies' to bat-size, gives them wings, and sets them to attacking his or her face.
A speciality of Ginny Weasley's, which she used on Draco Malfoy to escape Umbridge's office. It impresses not only Ron (OP33), but Fred and George, who use Ginny as an example of the principle 'size is no guarantee of power' (OP6)
Slughorn asked Ginny Weasley to join the Slug Club after seeing her cast a this spell on Zacharias Smith aboard the Hogwarts Express (HBP7).