In season four of HBO’s hit fantasy series “Game of Thrones,” Daenerys Targaryen lost control of her growing dragons. The hungry beasts terrorized the countryside in search of food and mischief. In one episode, the formidable black and red dragon Drogon flew between bucolic hillsides breathing fire at a herd of small, shaggy goats and snatching one for a snack. Drogon may be computer-generated, but the goats are real.