Tripe
From Cookipedia
Beef tripe is usually made from only the first three chambers of a cow's stomach: the rumen (blanket/flat/smooth tripe), the reticulum (honeycomb and pocket tripe), and the omasum (book/bible/leaf tripe). Abomasum (reed) tripe is seen much less frequently, owing to its glandular tissue content. Tripe is also produced from sheep, goats, pigs, and deer. Unwashed (or "green") tripe includes some of the stomach's last content, giving it an unpleasant odour and causing it to be considered unfit for human consumption.
For human consumption, tripe must be washed and meticulously cleaned.