This is a creation by MrBoltTron on Twitter

MrBoltTron’s Elthea and Matape Tortoise are a fun pair of characters. The choice to use blue on Elthea to contrast with the green makes for a nice overgrown look, as the green appears to be the result of plant growth and not necessarily the natural color of the character. The tortoise is not as complicated, though it makes great use of parts. It appears to use an octagon bar plate to attach the legs and head, while taking advantage of the studs in the center of the ring to build the structure holding the mask on. The base structure appears very versatile for getting a number of masks to fit.

As for constructive criticism, MrBoltTron mentioned plans to revamp Elthea, and I think I have an idea that would be suitable. He is excellent with high detail greebling, as evidenced by his other creations. Elthea already has some visible light-gray parts, some of it for holding plant parts in place while other bits appear decorative. I would suggest expanding upon that idea and building highly greebled skeletal limbs, to make it look like the remaining armor was either removed for, or eroded away by the invasive plant growth.

You can see more of his creations on Flickr and DeviantArt, as well as Twitter. He seems to favor highly detailed/articulated Toa and Titan MOCs, though has excellent creations of all sizes.