Make a primitive beast like an Alien, or make your own militaristic race like Predators, or make ANY type of beast you want.
Describe its personality, its culture, and its characteristics.
And then make a story of it killing people on a space ship Decide who the people are, and what they are armed with, and decide if your beast kills them or not, this has to be a story, at least 20 paragraphs, and describe how scared the people on, from 1 to 10, one is being in a paranoid state, and ten is in a psychotic state of fear.
And then, maybe our monsters could battle.
These warriors believe that pain is weakness leaving the body, killing some one is strength interring the body, and to DIE fighting, is an unlimited amount weakness leaving, and an unlimited amount of strength interring, the body.......