This powerpoint (complete with discussion questions) is great for students who are just being introduced to existentialism! It can be paired with The Stranger or other novels as well.
Since existentialism is such a strange concept in itself, this lesson uses a familiar children's book that can help make students feel comfortable with the introduction of such a philosophical topic.
This includes one powerpoint that uses "The Lorax" by Dr. Seuss to guide the teacher and class through the idea that morals are somewhat arbitrary. Links to "The Lorax" include an audiobook of the original version, as well as clips from the 2012 movie.
The slides are placed in order and include questions that a student may write an answer to or have a small group/class discussion.