Casu marzu is a type of cheese found mainly in Sardinia, Italy. It is distinctive in that it contains live maggots. The maggots — larvae of the cheese fly (Piophila casei), are translucent white worms about 0.3 inches (8 mm) long. When disturbed they tend to jump as much as six inches (15 cm) into the air.
Made from sheep milk, it moves beyond fermentation to decomposition as the maggots digest the cheese. The cheese fats are broken down and the texture becomes very soft with liquid seeping out of the surface. This liquid is called lagrima, from the Italian word for tears.
Some people remove the maggots before eating the cheese, but many do not.