This question more probably does not fit in most projects, but as a curiosity:
I know it sounds crazy but is it possible to make the mouse pointer go underneath an element in CSS (or any possible way!)? (Of course z-index does not work in this case. XD)
Or maybe create a pseudo mouse pointer customized for our webpage that in fact simulates the behavior of the user's real mouse pointer. I mean to create a virtual mouse pointer (a DOM element) that is indeed a replacement for the user's mouse pointer in our webpage (the user's mouse is somehow hidden) and our virtual mouse follows the real pointer's movement!