Negative Pressure (edit/re-post for Challenge)
We found the first one in Medical Bay.
Whether patient or experiment, I’ll never know. He—no, it, always it—lay back on a gurney. Straps crossed at forehead, chest, and hip. Padded manacles locked down the hands and feet. It had been a feisty bastard. It craned its head to look at us, and the strap across its forehead peeled back the weakened flesh like a hood, exposing a crosshatch of stingy muscle, a patch of yellow skull.
Don’t know how it sensed us. Couldn’t smell or hear us, or even see us—its decaying eyes had ruptured from the vacuum we had admitted to the ship, our first move to hinder any undead crew. It opened its mouth, and though there was no air to carry the sound, I swear I could hear the moan.
I raised my pistol and shot it from three feet away. A bolt of plasma erased its face and boiled away everything beneath. It thrashed a bit, but even if it hadn’t been strapped down, the cold had stiffened its joints.
I watched it for a moment, then spoke into my suit’s radio. “Clear, Medical Bay.”