What goes on in his head?

Tayson usually still wears footie-pajamas in the winter so that his feet stay cold at night. He ALWAYS kicks his covers off no matter what he is wearing or what the temperature is, so the footies keep him from shivering throughout the night. The other morning he zipped one of his bigger footballs inside his pajamas and thought it was the funniest thing ever. Then after a few more minutes of suspicious silence from his room, he came out like this:

His remark? "Look, Mom. I have lots of babies inside!" (Man, am I glad I'm not shaped quite like that when i'm pregnant!

Now what exactly was creating this unusual shape?

What a silly little goofball.