a bag
Examples
Marriage is like putting your hand into a bag of snakes in the hope of pulling out an eel.
Adulthood feels like walking around in the desert with a bag over your head, being bumped into by people who rob you as they bore you.
Technology has been defined, perhaps a little ungenerously, as "a long Greek name for a bag of tools."
You can only take out of a bag what was already in it.
You don't buy a cat in a bag.
A poor beggar is the one who begs without a bag.