Using a pet in a screenplay can create great originality and is always a crowd pleaser.
In a screenplay I am developing with one of my private students, a character has to choose to let a pet die for a greater scientific gain that will help humanity.
I asked my student to think about famous animal/human relationships in drama and consider how that scenario would play out in those stories.
For example, if Dorothy were a scientist and Toto were the pet used in an experiment, how would the story be influenced? If the scientist were Ahab and the pet, the White whale? Holly Go-Lightly and Cat in Breakfast At Tiffany’s?
Consider your own story for a moment? Does your character have a pet? If they did, what type of animal would it be? How would your main character react to sacrificing it to save humanity? How could you use this idea to improve your screenplay?