“I’ll remove your skin by biting into your FLESH!”
Dr. Skin, also known as Case D. Skin but was nicknamed Cassey by friends, love ones, etc. Skin was once an alligator who had his own lab somewhere in Canterlot, supported funds from the Princess herself, even though he couldn’t get certain resources from places such as the Everfree Forest, he was still able to substitute them with the resources he had, a proud and hard working Professor/Scientist the Princess would say. But one day the Dr. introduced his latest invention to Celestia, a robotic tentacle-like arm, the Doctor explained how if he researched it long enough it could be used for many purposes from construction to medicine, and even those who are missing a limb or two. But sadly Celestia noticed that this invention could be used for evil purposes, so she declined the idea. Angry at her decision, Skin decided to work on it in secret, but soon later Celestia learned about his secret and that it needed to end. Sent a party to Skin’s lab to take the invention and anything else that could be related to it, the party returns informing the Princess that the Doctor fought back, burned down the lab along with him and the invention still inside. Neither the body nor the invention has been found. This event has been kept under raps for at least 8-10 years. Two ponies were found dead in their home on the first year, nothing was stolen, and sightings of a cloaked figure have been spotted a few times at night in Canterlot.
Genetically enhanced his head to have a stronger jaw but changed his head into the look of a crocodile, does not like it when ponies mention that. Lost his tongue, body, and his right eye in the fire, so throughout the years Skin has been morphing himself into a sorta cyborg octopus. His tongue is a self created emerald he designed himself to be as soft as a cloud to prevent irritation within his mouth but can be as hard as rock if used as a weapon or if somepony tries to attack it. Right eye is cybernetic which can analyze the current situation and produce Skin’s chances of survival, scan ponies stats, many visions from night to x-ray and a lazer(cut through locks and such, not flesh). Arms are made of a stone/gemstone called “Moissanite” which is stronger than diamond, (long story short) has greater strength, very useful for testing applications and microelectronics. The crystalline structure is held together with strong covalent bonding that gives it’s strength. Lastly(but not the only thing), has little to no anisotropies occurring with in the crystal structure, thus giving it the ability to withstand high pressures and temperatures(this part reminds me of magic resistance sooo, good defense). Plus it’s hardness is graded at 9.25 on the Mohs scale which is second next to diamond. Moissanite is an actually thing, seriously look it up even I didn’t know this thing existed, and I play Minecraft for bloody sakes. Claws are an improved gold that he calls “Exfoliact” also with diamonds obviously. Organs are still intact but location is unknown but I will tell you this…their right under his snout. <His Snooouuut!
Ps: His bite is much more worse than his bark, and his finishing move.

MlpFim (c)
Art/Dr. Skin (c)