What are the big balls of gas that pumba was talking about?

Pumba was likely referring to stars in the context of the movie "The Lion King." Stars are massive celestial bodies made primarily of hydrogen and helium, undergoing nuclear fusion to produce light and heat. In the film, Pumba and Timon sing about the "big balls of gas" in a humorous way while looking at the night sky. These stars, including our Sun, are critical components of the universe.