Flash in the pan

The phrase "flash in the pan" refers to something or someone that initially shows promise or success but quickly fades or fails to deliver long-term results. It originated from the early use of firearms; a flash usually accompanied the firing of a flintlock pistol or musket, but sometimes the gunpowder in the pan would ignite without actually firing the bullet, resulting in a momentary burst of light and sound but no actual impact or lasting effect. Therefore, a "flash in the pan" metaphorically denotes something that has a brief burst of attention or success, but lacks substance or staying power.