Mary Zero was a young woman whose powers manifested and her parents immediately forgot she existed. She set out on her own, hoping to find someone who could see and hear her permanently, living in people's houses while they didn't see her, and stealing anything she wanted along the way.
While out "shopping" for her own birthday present, a group of thieves stole what she was about to steal, so she went with them to steal it from them. Agent X stopped the robbers, and acknowledged Mary's presence, apparently able to see and hear her. She instantly fell in love with him, and followed him around like a love-struck puppy thereafter, even though no one else could see who he was interacting with.
Powers and Abilities
None, since her M-Day depoweration.