It’s not like Macbeth is the only supernatural play. The Tempest’s magic. Midsummer’s fairies. The Winter’s Tale and whatever it is that happens at the end. And, of course, ghosts in Hamlet, Julius Caesar, and Richard III (am I leaving some out?).
But how do you stage the ghost of Banquo?
The key word, here, being “stage”… we’re talking stagecraft here.
The witches can enter and exit. From the sides, from “Hell” (the trapdoor in the stage)… the options are pretty much wide open (hell [and see what I did there], they could even descend from the rafters à la Peter Pan). The same for Hecate (though the use of “Hell” may be even more effective here).
But Banquo’s ghost?
It’s not like a film, where the ghost and just suddenly appear and disappear–which is what happens in Macbeth’s perception.
It would be kind of lame–and it has been in some of the productions that I’ve seen like this–to simply have the ghost walk on stage. Not very supernatural, not very shocking.
You could leave the seat empty, so that we as an audience see what the banquet guests see. We’d better understand Lady Macbeth’s chiding of her husband. That’s great if you want “realism.” But if you’re going for chills or scares (and I can definitely see directorial visions and concepts where this would be necessary), you really want Banquo’s “gory locks” (III.iv.52) on stage.
If you have a “Hell,” you could position the banquet table near (but not over) it. The actor could then pop up and escape when needed. That could work.
You could, I suppose, even have one of the party guests “become” the ghost, though how you’d accomplish that appearance change (and back) is almost as supernatural as the ghost’s appearance itself.
You could have a blackout of sorts, with only Macbeth in a single spotlight as he sees the ghost, then bring up the lights to reveal the ghost at the table. That might work.
You will have noticed a whole lotta “could”s and “might”s in the preceding.
How to do this?
[and don’t get me started on the apparitions in Act Four, Scene One…]