The Fox

One night Dad, Pete, and Sam saw a rather unusual sight out the back door.  It almost looked like a fox.

Pete/Dad/Sam: "Whoa, look at that!!"
Mom: "Oh, right,  The fox."
Dad: "What do you mean, THE fox"?
Mom: "Yeah, apparently there's a fox that has been roaming around"

Well, Dad/Pete/Sam found it thoroughly amusing that Mom referred to it as "the fox".  This was the running gag for a few days, which was rather amusing (except for Mom).