| Sometimes called a Ghilly suit, it's a military combat uniform festooned with strips of camouflaged fabric. The cloth strips are often supplemented by leaves and twigs both artificial and real.
All the strips of cloth and things cause the wearer to look shaggy and blend into the landscape. The more your outline is disrupted, the harder it is for an onlooker to recognize what they are seeing. The camouflage on a standard combat uniform is limited to color only, allowing a keen eye to pick out the wearer's outline and "see" them. The rough outline created by a Ghilly suit denies the observer the ability to determine the outline of the wearer, especially if they are hiding in heavy brush or undergrowth.
Ghilly suits are very favored by snipers, and are usually standard military issue for them. (Roninspoon corrected me by pointing out that ghillie suits aren't issued, every soldier makes his own. I would imagine that the creation of the suit is probably looked upon as a badge of pride and achievement.)
La petite mort Says that in the Australian Army they are also known as yowie suits. The "Yowie" is the name of a bigfoot-style mythical beast there. | 
