Picture book

This morning, Swe-cha brings out his picture book and opens it to the first page. Seeing that, I asked him to "show Mommy the car".

Swe-cha: [points to the yellow duckling]

Mommy: "Show mommy the car, honey. Where's the car ?"

Swe-cha: [keeps pointing to the duckling] "Aaaaah! Aaah!"

then, he looks at me while still pointing to the duck.

Mommy: "That's a duck."

Swe-cha: "Essss"

and then he walked away.

Ha ? What just happened there ? :)