Definition & Meaning of "like nailing Jell-O to the wall"

What is the origin of the idiom "like nailing Jell-O to the wall" and when to use it?

The idiom "like nailing Jell-O to the wall" is believed to have originated in the United States in the mid-20th century. Today, the idiom is commonly used to describe a situation where someone is facing a difficult or impossible task or attempting to achieve something that is highly unlikely or unrealistic. The idiom implies that the task or goal is so difficult that it is like trying to do the impossible.