Dadak

This weird spherical object was found on a college campus. It is hard like a rock, but is coated with something which has a soft texture. There are a few places where the coating has eroded and one can see the hard material inside. It seems to be natural rather than man-made. Any inputs of what this could be will be really appreciated. Location where it was found - Ahmedabad, Gujarat, India. Here is a link to the image of the weird object - https://ibb.co/hHxXSnB