Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - Game Master Ghosts, Spirits, we realy need them.

Creating a ghost of anything in the editor is actually rather easy, and the creature will be a ghost (it has spirit status) in GM Mode. Unfortunately it is tied to the scene it is placed in. Saving (exporting) the ghost, and even duplicating it, will make the duplicate or saved creature lose the ghost status.

At least when I try to do it.
I am no scripter and am basically just guessing what to do.