Mary (Greeks Bearing Gifts)

Mary was a prostitute on Earth. She would attract soldiers from the British Army and seduce them.

While running from one of her lovers, Mary found a Butterfly Person in the woods. The alien took over Mary, presumably killing her as well, and then killed the lover. While the alien possessed Mary's body, her body didn't age and could heal from gun shots and other wounds. (TW: Greeks Bearing Gifts)