What is the origin of the idiom "grasp at straws" and when to use it?

The idiom "grasp at straws" originates from the practice of a drowning person desperately trying to save themselves by reaching for any floating straws or objects within their reach. Figuratively, it is now used to describe a situation where someone is in a state of extreme desperation, willing to consider even the most unlikely or feeble solutions to their problems.