Joking.

Oscar (disapprovingly):  Why did you buy the strawberry bubble bath?

Mark:  Because there was a big man there who threatened to beat me up if I bought grape.

Oscar (wide eyed):  What big man was that?

Me: Do you think that really happened, or do you think Daddy is telling a joke?

Oscar:  Did that really happen or are you joking me?

Mark:  You’ve heard of the Wal-Mart greeter?  This was the Wal-Mart Beater.

Oscar:  Is Daddy joking me?