Quote - For the confused- a Ghillie Suit is a bunch of long, grasslike fibers or grass, held in place by a mesh. Usually covering a sniper. Looks like a grass pile with legs...;)

Originally used by Scots poachers (I've been told).

Scottish gamekeepers, actually.  To catch poachers.

Generally speaking, a ghillie consists of a mesh with long, stringy, canvas scraps hanging off of it.  You then stick material in it (grass, underbrush, whatever) that represents the vegetation cover of where you're going to be positioned.  Making your own ghillie is part of sniper training

And for a ragged old pile of canvas, it can be incredibly effective.  I've seen a demonstration where a small clearing in the forest, maybe 20 metres wide, looks absolutely deserted...and then something like two dozen guys suddenly stand up.