According to Catalog of the Unexplained, mantis beings are aliens that resemble the praying mantis, possibly travelers from a planet in the Draco constellation.
“Their color is black or green, and they have oily, pungent bodies. Their height is said to be between six and seven feet tall… They use clicking noises to speak to their own kind but communicate telepathically with humans.”
Mantis beings have been reported by victims of alien abductions, stealing them from their beds at night and using them for medical experiments, breeding programs and interrogations.