The title of this episode is an homage to both the motto of police departments and the classic Twilight Zone episode "To Serve Man", wherein an alien spaceship lands with a book of that name that turns out to be a cookbook.
Opens with the quote, "The beast was simply the Call of the Wild personified... which some natures hear to their own destruction.", from the story "The Wendigo" by Algernon Blackwood.
This is the second "monster of the week" that Grimm has shared with the show Supernatural. Both shows have featured wendigos and the weeping woman or woman in white, and both shows did so in consecutive or near-consecutive episodes.