The Darkness

In one scene, the dad opens up an e-mail from the mom, with a YouTube-looking link (watch?v=FDhoqY1grJY). If you paste that video ID to YouTube, it redirects to this movie's trailer.

The Anasazi Indians apparently spoke Tanoan, Acoma, Zuni, and Navajo, all Native American languages. However, they seem to understand the healers talking to them in Spanish, a language that is nothing like their languages.

The title doesn't appear until nine minutes in to the film.

A bleaker alternate ending was shot and test screened, where the Taylor family drive out and dispose the rocks into the ocean. Unbeknownst to his parents and sister, Stephanie, Michael still bears the fifth one, which causes the demon to drive the car off the cliff, striking and killing Peter and Bronny (sending their bodies airborne), and drowning Steph and Michael. The stones are then revealed to have washed up on the shore. When test audiences reacted poorly, the studio mandated a more happier ending to be shot. That aside, the scene can still be viewed on the Blu-ray.