Snake camo was a unique set of camouflage fatigues from the Metal Gear series. It had a snake like pattern, and had a variety of purposes, including either a heightened amount of camouflage capabilities, or otherwise being limited to a specific environment.
Metal Gear Solid 3: Snake Eater
It appeared in Metal Gear Solid 3: Snake Eater as an unlockable camouflage pattern for the Survival Viewer. It can be unlocked by defeating The Boss via non-lethal means, and then acquiring the camouflage as it is flung from her. It grants the player a decent amount of camouflage all over, second only to The Fear's Spider camouflage in terms of high camouflage in all areas.
Metal Gear Solid: Peace Walker
The Snake camo makes a reappearance in Metal Gear Solid: Peace Walker, although this time, it can be found at the Selva de la Leche area during the first mission there in Chapter 2. Unlike the previous time, its camouflage area was extremely limited, and although the description indicated that it's a mystery where it would be effective, the camo index indicated that it works best in ruin-type areas.