Casu marzu literally translates into English as “rotten/putrid cheese.” It contains live insect larvae, specifically the mangos for the Piophila casei cheese fly. The digestive action of the maggots breaks down the cheese’s fats, delivering a more fermented product. The maggots appear as translucent white worms, about 8 mm (0.3 in) long. It’s created by leaving a whole Pecorino outside with part of the rind removed to allow the cheese flies to lay eggs, which later hatch and eat through the cheese, making it very soft. By the time it’s ready for consumption, the typical casu marzu will contain thousands of maggots.