What are maggots, and what are they born from?

I've looked through a hand-full of answers here. I just don't understand it! Where do maggots come from?! We've been having a problem with fruit flies for A WHILE, and then the moths came... And now MAGGOTS!!! Don't tell me that they're fruit fly larvae, because these things are AT LEAST an inch in length, and THEY ARE NOT turning into flies anytime soon. *What are they born from?* Please answer, IT'S FREAKING ME OUT!!!!!