In the Harry Potter fandom, there is a curse named Bat-Bogey Hex, that "transforms the target's bogeys into large bats that fly out of the victim's nose".
In the Friends TV Series S02E03 right at the beginning of the episode, Chandler breaks up with a girl because her nostrils were so huge that "when she sneezed, bats flew out of them".
What is the origin of the reference to bats flying out of peoples' nostrils in these two cases? Is this just a coincidence or does it actually have some kind of cultural or linguistic origin?