Meet Citheronia regalis, aka The Regal Moth, aka The Hickory Horned Devil who's caterpillar stage can reach close to 5 inches long. Note the tiny Acorn Ant, Temnothorax sp., in the picture... if you can find it.
There she is! A colony of these ants could sooner live inside it than even dream of dragging it home.
For a better comparison here is my hand. The wingspan measured 6 inches from tip to tip. The above photos were staged. My brother who works down at the shore found this moth in a state near death and brought it home. In a vane attempt to get it (him? her?) to lay eggs I placed it on the Persimmon tree. (I've found Persimmons take forever to leaf out in the spring time.) Mothra died shortly before posting this... I think. It's actually yard to tell as it's in an almost catatonic state only moving the head muscles.