I’m looking for a kid’s/youth book that had fantastic full page illustrations, and was fairly long. It featured a goblin/elf/hobbit-like creature who went on a quest, and at the end of the book, there was a large stone staircase where you would turn to stone/statue, but the main character managed to avoid being turned to stone and complete his quest. I can’t remember much more than that, but the illustrations were great, and very dark in colour.