if you can get it, read the novel SHELLEY for example . .
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there, an insane "Scientist"(he was, in reality, only the son of some rich guy and stuck on a bad Frankenstein BTL) took parts from shapeshifters and tried to reanimate them, after having sewn them together as he saw fit . . only reason it DID work was an shadow spirit just happening to be curious and close by. Said spirit taking possesson if the Corpus Delicti and thus making it habeam corpus animatus