What movie is this, I want to know so I can get over a fear it installed in me at a young age.?

I remember watching a movie a few years ago. I only remember little details and scenes, but I'm curious about the movie. The main character was a woman, and she was, for lack of better word, being hunted. And when the hunters would draw near, becuase they living in the Darkness and couldn't go into light, Lights would flicker before fading completly. If one stayed in the darkness, they were draged into it, where they were eaten. I remember how in one scene, it was explained that these creatures were the ones people were afraid of as a kid, the monsters under the bed. They would drag you into the darkness and implant a tracking chip, which would reappear a few years later when you were big enough to eat. I was wondering if anyone knows the movie I am talking about. If you know, could you let me know? Thanks.