Don’t blink.
Stone angels covering their faces, as if crying. They only move when nobody is looking at them, so the moment you blink, they’re closer. Their touch doesn’t kill: it throws you back in time, and they feed on the energy of the life you would have lived.
Steven Moffat created them for “Blink” (2007), one of the most loved episodes of Doctor Who, after finding an angel statue in a Dorset graveyard that had disappeared when he came back years later.