Bivy sacks are for camping, usually used by ultralight backpackers due to their light weight and minimal size. I created one thats thick, and very durable and uses various camo covering to match the surrounding environment. Instead of it being out in the open, it uses whats called "Drag Bag" methodology. In other words, build it, then drag it inside a fallen or downed tree for further camo or stealth qualities. Its great for hidden camping, hiding from or viewing wildlife or even Bigfoot. Its heavy duty enough that the idea is to leave it set up for a month or two. Let the animals get used to it being there, let it become part of the natural environment. Then, sneak in quietly and slip inside the bivy and the animals or maybe even Bigfoot wont suspect anyone is there!