Does the animal kingdom hold the key to immortality? When humans are injured, we have the benefit of medicine and surgery. But these skills pale in comparison to nature's super healers. Some creatures have evolved to literally grow regrow parts of themselves! What's the salamander's secret to growing a new limb? Or the spider's ability to advance its armor. Do sharks really have endless teeth? Why do deer grow weapons on their heads only to lose them in the winter? What if we could use our own organs as weapons like the mighty sea cucumber? And is the key to every lasting life hidden in a jellyfish at the bottom of the ocean?