Casu Marzu

Casu marzu, roughly translated into English, means “rotten cheese,” and if the rotten part isn’t already bad enough, it’s also known as “maggot cheese.” This Sardinian cheese is derived from pecorino and is typically soaked in brine, smoked, and left to ripen in a cheese cellar. Then cheese makers set it outside uncovered, with part of the rind removed, allowing cheesing flies to lay eggs inside it. The eggs hatch into maggots, which start feeding on the cheese. The larvae themselves appear as translucent white worms, roughly 8 mm (5⁄16 in) long. They produce enzymes that promote fermentation and cause fats within the cheese to decompose. The cheese becomes super-soft with some liquid (called làgrima, Sardinian for "teardrop") seeping out and leaves a burn on the tongue when eaten.
Casu martzu is considered by Sardinian aficionados to be unsafe to eat when the maggots in the cheese have died. Because of this, only cheese in which the maggots are still alive is usually eaten, although allowances are made for cheese that has been refrigerated, which results in the maggots being killed. When the cheese has fermented enough, it is often cut into thin strips and spread on moistened Sardinian flatbread, to be served with a strong red wine like cannonau. Because the larvae in the cheese can launch themselves distances up to 6 in. when disturbed, diners hold their hands above the sandwich to prevent the maggots from leaping. Some who eat the cheese prefer not to ingest the maggots. Those who do not wish to eat them place the cheese in a sealed paper bag. The maggots, starved for oxygen, writhe and jump in the bag, creating a "pitter-patter" sound. When the sounds subside, the maggots are dead and the cheese can be eaten.
Casu marzu is not in compliance with European Union hygienic standards and has been declared illegal. It is also illegal in the United States because it is unpasteurized and has more than six mites per square inch. (The microscopic bugs live on the surface of aged cheese.)