Balut is an 18 day old incubated duck egg. The Philipinos eat them like crazy. Peel the shell, add salt and vinegar, and eat it all, even the feathers and the head. Type in balut in youtube and you can see videos of people trying to eat it.
More information than I really wanted, though it sounds a bit like the Chinese ‘Thousand year Old Eggs’, a hyperbolic name.
My ship (Navy, 1985-1991) went to the Philippines a number of times in the late 1980s. We called balut "the egg with legs"....
From http://www.deependdining.com/2005/09/balut-egg-of-darkness-pinoy-pinay.html
Balut is the culinary heart of darkness. If you eat it, you have reservations about doing so. If you know about it, you have strong opinions regarding it. Ask for it in a restaurant and the clerk will visibly react. Devour it at a table with others who aren’t eating it and you’re guaranteed to dine solo. Explain balut to the uninitiated and be prepared for your audience to run away from you as quickly as possible while seeking sanctuary in something comforting like a Ding Dong. I know all this because I’ve had these things happen to me whenever balut is present, physically or conversationally. I have struggled and continue to struggle with eating balut. Superman has his kryptonite and I have balut. It is probably one of the (if not THE) exotic foods I fear most. In fact, I have been putting off reviewing balut for almost a year now for this reason. Why am I so freaked out by balut? Well, how much time do you have? For starters, balut will haunt you after you ingest it. It stays with you forever. I’m not suggesting that I believe in the ghost stories about being possessed after eating balut. I’m speaking more to the traumatic imprinting that might occur when you consume this culturally complex cuisine. Even when I try hard not to think about what I’m eating, somewhere in the dark recesses of my mind I’m aware that I’m eating a fetus, life that is yet to be, something unborn, taboo food. Also, this awareness has nothing to do with political-religious beliefs. It is simply the unappealing idea of eating a fetus.
Other entries on my Top 10 list include Casu Marzu, Baby mice wine, Rocky Mountain oysters, and any kind of brain.