The NSA Elf on the Shelf is a special elf sent from the National Security Agency to help intelligence agencies manage their naughty and nice lists. When a family is assigned an elf - and every family is! - the elf receives its magic and can fly every night to Langley, Virginia or the J Edgar Hoover Building in Washington, DC, or just to your local sheriff, to tell all about the day's adventures, telephone calls, and - whenever possible - private thoughts. Each morning, it returns to its family and hides in a different place to observe. (Of course, in reality, the elf doesn't fly anywhere but is in constant radio communication with intelligence and law enforcement, and it doesn't hide just one place, but everywhere! Look under your bed, it may be there right now!)
There are two rules every child knows about the NSA Elf on the Shelf. (And if the child doesn't know them, ignorance is no excuse.) First of all, the elf cannot be touched, not even with a court injunction, so don't even bother trying. Secondly, the elf is forbidden by NSA magic from leaving its post or speaking directly with its family. So there's no use shouting, "I know you're watching, why don't you show yourselves?" or "Leave me alone, for God's sake, leave me alone! I haven't done anything!" When you say things like this, you just make the elf laugh. Ha-ha-ha. Then he reports your remarks to Washington.
