(1) A plastic bag carried in case of unanticipated bowel excitement. A whoopie-whoop swell foop scoopy-scooping human-poop feedback looper. Use it, tie it, fling it.
Also known as a flyaway toilet or helicopter toilet, this is a simple hobby that everyone can take up. Not biodegradable or anything, but a fun way to interact with people you dislike, as long as they're close enough to nail in the head and yet far enough away to give you a decent running start.
Gastro Girl does it so you can too. ( http://bit.ly/1uPxJZU ) Plus, she has suggestions about how to handle those oily stains.
(2) A bag kept in reserve for dealing with memory-related incontinence. A catch-all container for any last minute or almost-forgotten items you need.
Forget something, only to recall it at the last moment, after you're already packed? Just droop and drop by leaning over and dropping said thingy into your oops bag, then put off worrying.
Once you reach the trailhead, then you can worry about how you're going to carry the damn bag. If you are really slow upstairs (no, don't write in to share your stories, please) you can lash the bag onto your pack and later hang it overnight right with your food. Sort things out the next day when you need to repack your pack in the first on-trail morning's early light.
Some people in fact live their whole lives this way.
(3) Yo head, dude. The place where you keep a record of your dumbs, so you don't have to invent them again later. It's like, science 'n all.
(4) An emergency package of the little things you might need while you are out and about. It covers oops moments that arise.
(5) Etc: https://bit.ly/3xXQgdH
See tabs at the top for definitions and books.
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