A commission from back in March for wolf-butt.tumblr.com! Designing monster pals is a lot of fun: the Crystalupus is based on the gemstone Resinite/Rock Amber. He also comes with a bit of story:

“The Crystalupus dwells in mineral-rich mountain caves, and is an omnivorous scavenger/opportunity hunter. While its diet consists largely of the rock and soil from its home, which enables it to form crystalline growths on its body, it will also feast on insects, plant matter, and the carcasses left by other predators. It is territorial, but unlike other territorial creatures, it does not hunt intruders. Instead, it waits in the dark of its cavernous dwelling and uses luminescent glands under the skin to cause its crystals to flash and glow, mimicking the glint of actual gemstones embedded in the rock, luring adventurers and anything else unwise enough to venture close into attack range.“