What is an owl snake?

Owl, originally a bird, looks like an owl, while owls and snakes generally describe evil and evil. Moreover, as an idiom, owl snake is generally associated with fierce snakes and ghosts, which is a metaphor for ugly people. From Lu Xun's book (the book of two places. To Xu Guangping 1 12). "I don't ask if this is an enemy, an enemy or a fierce snake ghost."