Webster's defines parasites as "the scariest things on earth, that threaten our very way of life." Or at least that's how they should define them. Parasites are utterly frightening and the effect they have on their hosts does not tend to be pleasant. Some of them out there are truly terrifying and the little buggers live absolute crazy life cycles. Check out the list below for some of the craziest parasites and their odd life cycles so you know exactly what to avoid.