Manananggal

A variety of Aswang native to the Phillippines; appears as an attractive, elderly woman and feeds on pregnant women. Children born with deformities are said to be the result of a Manananggal attack. They travel by dropping their lower half and flying their upper half around to hunt. Destruction: find the lower half and cover with salt, garlic, or ashes. [Dex] Vietnam, ‘68 Corvin has more info.
Many manananggal stories greatly resemble those from European mythology of Hags, including some details on repelling them. Corvin and Dex speculate the creatures were one species at some point in distant human history.