The history of theatre is littered with ghosts and spirits. From Hamlet to ghost lights to Ancient Greeks to contemporary plays, theatre has always explored the nature of here and there, life and death, reality and unreality. They are one of the most used and accessible tropes there is.
In theatre, film, and the performing arts in general, there is a very common case of what I call two-dimensional racism. This is the sort of optics-based casting that is simply meant to check off casting people of color like there’s a quota to fill; there is no depth to the diversity—it is two-dimensional.