What was that sound? I'll tell you what that sound was.

At night, before my three year old (M) falls asleep, she often says something charming while she's tucked in and drifting off. 

M: What was that sound?

Me: It was the bed creaking.

M: No. It wasn't the bed creaking. It was a frog outside in the pond on a lilypad.

Me: Oh.