"Open fire!" Steber screamed and aimed his rifle directly at the Beast. He squeezed the trigger and in the blink of an eye, a dozen bullets tore through the monster's chest. Porter did the same and Mitchell and Cray shot off several rounds from their handguns. The Beast screamed again, this time in a much higher pitch than before. In unison, the three remaining marines and Cray cried out and were forced to their knees, each dropping their guns and covering their ears. His head ringing as if an explosion had just gone off inside his skull, Steber squeezed his eyes shut and was barely aware that blood was flowing down both sides of his face from ruptured eardrums. There was more to the Beast's scream than pure sound - it was a physical power similar to a sonic boom. His eyes still clenched shut; Steber groped the floor for his rifle and was less than a foot away from it when he felt the Beast's massive weight land on his back, grinding him into the floor. The Beast roared again and Mitchell and Porter lost consciousness. Cray was the last one alive when the Beast bit him on the shoulder. The scientist screamed and fired blindly in all directions. None of his bullets hit the monster, which continued to disembowel the frantic doctor.
Satisfied that all the intruders were dead, the Beast howled once more before returning to the dark room from which it had come from. There it crouched down into the position it had taken before the marines arrived and drifted back to sleep.
You are dead.