During the beginning, although it was offscreen and more of a Tear Jerker. Morgan killed his slowly going insane dog to protect his sister. You heard it right, Morgan a child with asthma, who nearly died during a panic attack later in the movie protected his sister from a mad German shepherd. What makes it more badass was the stoic way he described what happened.
Merill Hess with a baseball bat, versus an alien invader.