Watch World's Weirdest Season 4 Episode 4 Online

If it creeps, crawls, buzzes or sheds its exoskeleton, there's a chance it could cure an illness that's stumping modern medicine. Parasitic worms, flesh-eating maggots, blood-sucking leeches, and skin-nibbling fish -- man runs from these creatures and often tries to eradicate them. But scientists and MDs are finding out just how much we need these creepy-crawlers to stay healthy. We explore the healing properties of the animals many think are disgusting, but sometimes turn out to be lifesavers.