This is my rendition of a Stalnox (monster from Zelda, Breath of the Wild) using only pieces from the Lego set Dinosaur Fossils (#21320).
I never made any MOC, but being a big fan of the Zelda series since I first played Link's Awakening on my old game boy, and seeing the Dinosaur Fossils (#21320) set, I was very tempted to take a stab at it. Limiting myself to the pieces given in the Fossils set was both challenging and exciting. To be fair, I don't think I would have reached a pleasing result if I had been given all the possible Lego pieces, it would have been far too overwhelming, and would leave me no excuse for the dissimilarities...
This Stalnox is leaner that the original chunky mini-boss of Breath of the Wild, but I am rather happy with the result, it looks great on my desk, and I'm pretty sure it throws pieces of its own rib cage (as in the game) when I don't watch. That or they fall on their own, but the former is more likely.
I started with the rib cage, back and front. It looked good, but attaching them together was challenging. The front of the rib cage is suspended to the clavicules, which are sinusoids in the 3 dimensions. I nearly gave up, but at a point I got lucky and managed to find a structure both fairly sturdy and visually pleasing.