I have my uncle's CBI (China/Burma/India) bullion patch from his service with Gen. Merrill's Marauders during WWII. Terrible, traumatic mission. He said they ended up eating their pack mules to stay alive in the jungle because they couldn't get resupplied by air. There is much more to the story - was made into the movie Merrill's Marauders. They were the 5307th Composite Unit, and it was volunteer-only.
http://www.marauder.org/history.htm
"President Roosevelt issued a Presidential call for volunteers for "A Dangerous and Hazardous Mission". The call was answered by approximately 3,000 American soldiers. The volunteers came from State side units, from the jungles of Panama and Trinidad they came, from the campaigns of Guadalcanal, New Guinea, New Georgia they came, to answer the call, some battle scarred, some new to the ways of war, each different but with one thing in common. They Answered The Call.
The Unit was officially designated as the "5307th Composite Unit (Provisional)" Code Name: "GALAHAD", later it became popularly known as "MERRILL'S MARAUDERS" named after its leader, Brigadier General Frank Merrill. Formed into six combat teams (400 per team),color-coded Red, White, Blue, Green, Orange and Khaki, two teams to a Battalion, the rest formed the H.Q. and Air Transport Commands.
After preliminary training operations were undertaken in great secrecy in the jungles of Central India, the Marauders began the long march up the Ledo Road and over the outlying ranges of the Himalayan Mountains into Burma. The Marauders with no tanks or heavy artillery to support them, walked over 1,000 miles through extremely dense and almost impenetrable jungles and came out with glory."
He saved a tattered old copy of their unit song and it is pretty cool, pic related.