[The Leader]

I think it says:

There was a boy, who was filled with joy, everytime he got a toy
One Christmas, a package came for the boy in the mail, and the boy’s joy filled to the brink
And when he opened the package, the boy was so excited, he ran smack into the sink
Inside the box was not a pair of socks, or a sweater, or a mop
The boy, who got a new toy, was so filled with joy, his head exploded with a pop