Sam the Dog, I Am Legend
Will Smith has played some seriously emotional roles over the years, but nothing touches the scene when he had to kill his beloved German Shepard. For those who don't know, his dog got bit by a zombie dog, and Will Smith had to take matters into his own hands and put down Sam himself. Do yourself a favor and cover your eyes for this scene.
Charlotte, Charlotte’s Web
Charlotte's death was somewhat coreographed contextually, but the emnotional impact she leaves when she does die hurts every time you watch this movie. Seriously, Charlotte and Wilbur's relationship is so beautiful, and Charlotte's death is entirely unexpected to Wilbur. His reaction to her willingness to go is heartbreaking.