Skinwalker

Based on old Pueblo legend, an evil spirit that could wear a persons skin as if it was his own. It was feasting on those who had magic in their blood until a Native American Medicine Man battled the Skinwalker and imprisoned it in a cave near the mountains. The Skinwalker could not leave the cave without being in possession of another's body.

Flash-forward to present day:

A college student, while working on a dig in Arizona, comes across the cave and is taken over by the Skinwalker, then killing her collogues and others. Her best friend, who has some ability with magic, must now clear her best friend of the murders and along with two others, kill the Skinwalker.