Let Us In

The film begins with the following text describing the urban legend:

"Black-Eyed Kids:

A contemporary urban legend consisting of paranormal creatures that resemble children with pale skin and black eyes who are reportedly seen hitchhiking, panhandling, or are encountered on doorsteps of residential homes.

Although labeled an urban legend, there have been hundreds of documented cases of individuals across the world coming into contact with these creatures...

...who have never been seen or heard from again."

Christopher vanishes standing near Emily without a sound or trace. It's implied multiple times that the Jungspars can't abduct people without their consent. Christopher, as scared as he might get sometimes, wouldn't say yes when Emily's with him.