An Alternate Reality Game (ARG) is an interactive narrative that uses the real world as a platform and involves collaborative storytelling between players. ARGs are often elaborate mystery stories played out across multiple real-world mediums like websites, emails, and phone calls. A notable example is the AI: The Somnium Files ARG which involved over 3 million active participants in a science fiction murder mystery story. The document then describes the Existenz ARG created by the author for 30 friends in 2014 which used fake websites, social media accounts, 3D printed objects, and live events to tell an immersive transmedia story.