flash in the pan (noun)

1. The new cult leader turned out to be just another flash in the pan, gaining many followers initially but ultimately failing to deliver on his promises.

2. The bold and trendy architectural design of the building quickly became outdated, making it nothing more than a flash in the pan.

3. The artist's debut exhibition was a huge success, but he turned out to be a flash in the pan, never again achieving the same level of recognition or acclaim.

4. In Greek mythology, Icarus is often considered a flash in the pan, as he soared to great heights with his wings made of wax but then plummeted to his demise when the wax melted.