Like last night, when he kept calling Middle Daughter names like "Stupid" and "Loser" and "Butt". In The Boy language, these are Seriously Bad Words. So, Husband told him to knock it off. More than once. Finally, Husband gave The Boy an "or else".
And The Boy looked him in the eye and said "You're a Stupid Loser Butt!"
You can paint your own picture of the hilarity that ensued.