Gutless, buttless and surprisingly versatile
These 6-foot-tall, red-tipped characters, also known as Riftia pachyptila, have no mouth, digestive tract, or anus. Instead bacteria living inside the tubeworms’ bodies in an organ called a trophosome convert carbon dioxide into organic carbon by using chemical energy. This makes them the "first known [macro] organism that makes organic carbon by different means", according to a Woods Hole press release about a paper in Science by Stefan Sievert and colleagues.
[Not to be compared with Robert Gates, late of the Iraq Study Group, now defending George W Bush's new strategy]