Something's at the door...

A mysterious figure gets out of a delivery truck, as they do they head over to the porch and gently set down a brown cardboard box, the kind you'd expect to be containing shoes, or a video player. The figure proceeds to knock on the door before speeding away, hopping into the truck and driving out of sight before the owner can respond. The box stands there, boring and unassuming, but what will be found inside is anything but. Before getting to that, though, the question is...