It looks like a cheap fantasy book cover

I loved creating these, specifically creating the (in my opinion) great colour palettes, and showing them side by side creates a great sense of contrast!

The image on the left was created first, in which I used an...interesting technique to create the almost smoky effect in the background, which consisted of using a wide leaf brush on low opacity (5%) and layering it at different sizes over and over while changing the saturation to match where in the image I'm highlighting~ but I digress.

The image on the right is a duplicate with the hue shifted, smudge used to create the stalactites and more, smaller texturing used on the ceiling.

I'm completely set in the idea of this being ideal for one of those 50p sci-fi books you can pick up from charity shops though...