Green beret
When visiting the Special Forces at Fort Bragg on 12 October 1961, President John F. Kennedy asked Brigadier General William P. Yarborough to make sure that the men under his command wore green berets for the visit. Later that day, Kennedy sent a memorandum which included the line: "I am sure that the green beret will be a mark of distinction in the trying times ahead". By America's entry into the Vietnam War, the green beret had become a symbol of excellence throughout the US Army. On April 11, 1962 in a White House memorandum to the United States Army, President Kennedy reiterated his view: "The green beret is a symbol of excellence, a badge of courage, a mark of distinction in the fight for freedom". To no avail, both Yarborough and Edson Raff had previously petitioned the Pentagon to allow wearing of the green beret. The President, however, did not fail them.
Green Lantern Corps
"The Corpse" is an elite, top-secret Black Ops division of the Green Lantern Corps. Members of The Corpse are not restricted by the same rules that regular Lanterns follow, and they perform the darkest, most dangerous missions and are allowed to use lethal force. These members do not use Power Rings; instead, they swallow special coin-like disks that give them all of the powers of the standard ring with a charge that lasts five earth days. These disks produce purple energy instead of the traditional green. Members of the "Corpse" do not wear Green Lantern uniforms, or display the Green Lantern symbol. Instead, they seem to prefer black uniforms that have no symbol.