A balut is a fertilized duck embryo that is boiled alive and eaten in the shell

Popularly believed to be an aphrodisiac and considered a high-protein, hearty snack, balut are mostly sold by street vendors in the regions where they are available. It is commonly sold as streetfood in the Philippines. Balut eaters prefer salt and/or a chili, garlic and vinegar (white or coconut sap) mixture to season their eggs. The eggs are savored for their balance of textures and flavors; the broth surrounding the embryo is sipped from the egg before the shell is peeled, and the yolk and young chick inside can be eaten. All of the contents of the egg may be consumed, although the white may remain uneaten; depending on the age of the fertilized egg, the white may have an unappetizing cartilaginous toughness.

In the Philippines, foreigners are always challenged to try this delicacy... although it may look disgusting, it really taste so good.