I don't think there's any explanation necissary.
OK maybe there is. But I can't for the life of me imagine what that would be.
Although Transbuddha got it pretty close:
"Imagine if you will that Aqua Teen Hunger Force’s Carl was shoved into a Unicorn body and then pestered by a similarly unicorn’d Walter and Perry from Home Movies, and then hammer it down with a PCP laced mallet.
Yah, that still doesn’t explain it."