Many species of wasps lay their eggs inside caterpillars. To make this possible, the wasps' have a secret weapon in the form of a dose of virus-like particles that are injected along with the eggs.
Not only do these disable the caterpillars' immune system to stop it attacking the eggs, they also cause paralysis and keep the host from pupating - turning the caterpillar into an eternally youthful larder and nursery for the wasp grubs. (Source The New Scientist)
In the picture a parasitic wasp lays its eggs into a caterpillar, at the same time delivering a hybrid virus.
"I do not understand where this "beauty" and "harmony" are supposed to be found. Throughout the animal kingdom, animals ruthlessly prey upon each other. Most of them are either cruelly killed by other animals or slowly die of hunger. For my part, I am unable to see any great beauty or harmony in the tapeworm. Let it not be said that this creature is sent as a punishment for our sins, for it is more prevalent among animals than among humans. I suppose the questioner is thinking of such things as the beauty of the starry heavens. But one should remember that stars every now and again explode and reduce everything in their neighborhood to a vague mist. Beauty, in any case, is subjective and exists only in the eye of the beholder. "
There was no pre-death biology. Death is built into the system of life in the Universe. The Biblical account claims there was a fall from immortal to mortal. Life is mortal. The reality of the human condition is right there to say for anyone who will take a stroll into your local hospital. These bodies were never immortal. They are part of the Universe which itself is dying on a much larger scale.