NASA Debunks 'Cannonball' on Mars which Curiosity Found—But What is It?

There are many things found on Mars, but what piqued the interest of conspiracy theorists and believers of alien life forms is the "cannonball" looking object found on the Red Planet's surface. This object was found by the Curiosity Rover on its earlier missions, and it was able to capture an unusual almost perfect spherical object that indeed resembles a cannonball.

However, NASA clarified that this is not a cannonball, but what is it exactly?

NASA Debunks Cannonball From Mars, Found by Curiosity