The head and antenna are very challenging to print. Because it is football pigskin shaped, you have to be creative during printing. For the Head, I lay it upside down while generating supports only for the ear. For the antenna, I lay it in a tilted fashion so that the end that will be fitting in the head wont be bothered by supports.
The spring is a derivative of 3D printy's spring from his emoji collection, of which you can find here.
The author hasn't provided the model origin yet.