Compliant. That was a good word for how the Wendigo had behaved for the past few years. For this compliance, it had been permitted certain comforts, chief of which was the access to the kitchen, but second to that was the little speaker on the top of the far wall, just below the ceiling. In flowed the dulcet tones of the Adagietto of Mahler's Fifth Symphony. The Wendigo was cutting onions, but paused its chopping to shut its eyes and listen. It had never used the internet, never seen a cellular phone, or indeed touched any phone for the tenure of its incarceration. It had been allowed books relatively recently and thus was comfortable.
They never let it perform surgery.
Its eyes opened again and it continued to chop the onions. Occasionally it glanced to the small ornate mirror on the opposite wall. Thrift shop wood with a $10 gold leaf job, but at least it was pleasing to the eye. And it knew what was on the other side, oh yes. Its eyes shifted briefly and it caught a glimpse of a thick black shape that happened to be attached to it. For many years it had lived here with only minimal probing, but in the last month some slack jawed researcher had decided to test its regenerative capabilities. It had made a mistake, informing them that it believed that it could grow indefinitely, and now it payed the price.
Typically it would gorge in the evening and wake up the next morning with a new growth of black skin, hair, and feathers all over its body. Some days it grew antlers, other days it awoke with strange prominence on its face that misshaped it. It had adapted early on to showering regularly and using its teeth and claws to tear away the excess material, leaving behind its current form, a well-dressed eastern european man, with only a smattering of tiny black feathers on its forearms and beady maroon eyes to betray its true nature - some days it kept the antlers, it depended on its moods.
But now it was not being allowed to shed the flesh from its left arm, and the limb had become substantially engorged to the point of discomfort and distress- not that it betrayed those emotions on its face, it rarely displayed negative emotions in any sort of obvious way, except when forced. In fact, it was quite pleasant to the researchers and nervous little men who came to poke and prod at it. It even had little wrinkles around its eyes, crows feet that crinkled when it smiled. It would not smile at the rat bastard meatsack pile of filth that did not let it shed its arm.
It lifted the cutting board, onions, and knife with its unaffected hand, then scraped the onions into a glass bowl, then it set the cutting board in the sink, and washed off the knife. It was still for a moment, not making a peep. Then it was a flurry of movement, raising the knife to chest-level, then shoulder-level. It didn't hesitate as it jammed the knife into the flesh of its bicep, tearing through the leathery black flesh. The edges of it began to shake, as if the man wasn't quite there, replaced with a silhouette of black. It snarled as it worked the blade through its arm.