I just stumbled over the seemingly popular interpretation that Mufasa's ghost was only in Simba's mind and that's why he didn't tell the truth about how he died. I was like 'Whaaaat?!' That never crossed my mind, in all these 15 years.

I guess it is kinda left up to the viewers interpretation in the film but Mufasa truly appearing to guide his son, fits the theme of the story much better than just Simba's imagination.

Rafiki had summoned him. You know Rafiki was able to do weird stuff, such as seeing that Simba is alive and where to find him, por doing something to the dust in the wind that had...