In the past when I tried to cut my weight, long before the Internet, I used to leave my heavy standard T-rest home and just pack a Space Blanket Brand Bag. I'd fill the bag with leaves during my Fall hikes and sleep almost as comfortably as on my T-rest. In the morning I would shake out the leaves and pack up the bag, and hike on. Of course the bags are not made for this so care had/has to be used in this application. A ground sheet is a big plus, as is care used to stuff the bag. Also a large garbage bag or two could function this way and pack smaller than a pad. Only caveat is you need to know in advance that materials would be available for use, or else you'd be sleeping on the hard ground.
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PEPPER SPRAY AIN'T BRAINS IN A CAN!