5 going on 15

Daniel has turned into a teenager on me. When I tell him to do something, there's this great big sigh. Or worse, this "hmpf" noise. We've been dealing with it for a while - talking about how rude that noise is and how being disrespectful to mom and dad is as bad as not doing what we ask at all. It came to a head last night.
I put him to bed - twice. He'd lay there for a few minutes making that "hmpf" noise, then pop up and flip his light back on. I went in again, told him it was bedtime and he was not to get up again or he'd be risking a spanking. "Do whatever you want to do, mom," he said in a tone I normally associate with rude 16-year-olds. Only, his dad heard that one.
"You are going to lose a train for speaking to your mother that way," dad decreed. "Thomas isn't rude like that, and if he is, he gets punished, too."
"Fine," shot back our teenage-posessed child. "Take all my trains. I don't care!"
So we did. And it turns out he does care. But as we were scooping trains into the nearest storage bin and he was wailing away about it, the message was delivered: "You can't just say things to us and not expect there to be consequences. Don't say it if you don't mean it, and think before you are rude to us."
God, let the message sink in. I want my sunshiny child back.
--Misty