That is a balut egg. A balut is a fertilized duck embryo that is boiled 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. They are common, everyday food in countries in Southeast Asia, such as Laos, Cambodia and Vietnam. They are often served with beer.
I remember watching a program on freakiest food on AXN. While this certainly is one of the weirdest looking and yuckiest ever food, I would like to try some. Egg = good, duck = good!