Have you ever thought of making a tomb like what is shown in the videos below?
Video 1
Video 2
The levels are from two fan-games that I found out about.

Nope, never. Interesting concept tho. I'm not even sure how one would go about creating something like that.

The usage of wall and floor textures that have an organic design to them can go a long way (especially if you make them pink, purple, or red.) Doors and other dungeon elements can be given such textures as well.