Greb-Nefual E-neg!

The kids watch a scary old horror movie where a character speaks a certain ancient-language phrase meant to curse the victims to the shadow realm. That phrase? Greb-nefual e-neg! The movie scares some of the kids, but Girl calls it all a bunch of hocus-pocus and speaks the phrase aloud herself. Nothing happens. But one by one, the siblings start disappearing, leaving only a superstitious Boy.