I have this concept for a piece that I'm dying to try but it involves a ghost/spirit horse. I've seen it done a fee times but have searched for tutorials and can't find much to help me. I would very much so appreciate it if someone could briefly walk me through how they make their horses/critters ghostly! I use IbisPaint though any tutorial on any platform would do.

Hi! Not sure if this will help you because I tend to redraw my entire horse but here goes :)

the first thing I do is trace and fill my base layer like normal. This is the solid base colour I want the horse to be.

Then I do my shading and lighting-usually I do three layers of each.

Then I simply remove my base layer and play around with shading & lighting layers until I like it!

here's a few examples of me just removing the base from some of my works

Hope this helps a bit!