Well, I was recording my own voice to use for lip syncing as animation practice. For an experiment I changed the pitch of one line ''One day, this will be mine - all mine,'' and thinking it sounded quite a bit like Mufasa (plus being similar to young Simba's ''And I'm going to rule it all!'' line), I decided to do a little animation using it. I then had to deepen another recording to make Scar's voice.
It's not finished (but close!) - here with have the younger Mufasa and Scar, with Mufasa teasing his younger brother a bit . . . https://www.youtube.com/watch?v=2jjq1dh7D6w