Paracelsus once proposed that he had created a false human being through his science. Called a homunculus, this creature stood no more than 12 inches tall and did the work usually associated with a golem, an artificial creature from Jewish tradition. However, after a short time, the homunculus was known to turn on its creator and run away. Paracelsus’ recipe consisted of a bag of bones, sperm, skin fragments and hair from any animal of which you wanted the homunculus to be a hybrid. This was to be lain in the ground surrounded by horse manure for 40 days, at which point the embryo would form. This supposed beast relied on the theory of spontaneous generation.