Hooray, now someone going to have to mercykill the Dibnys.
On the bright side, it might be something like the energy of the rings animating the bodies, with the decomposition of the brains and the Evullll energy used in the possess causing uncharacteristic behaviour.
Rather than soul-enslaving, alien magic that entombs people's souls in a decaying prison of flesh and forces them to attack their friends and loved ones, kind of deal.