James Gunn says he made up the Infinity Stones lore for the MCU in Guardians of the Galaxy in just 3 minutes, which later became the foundation for Avengers: Infinity War (2018). “I never understood what any of the phases were in Marvel. I don’t know what any of it means.” Gunn said Marvel simply asked him to explain what the Infinity Stones actually were. “When I wrote the scene with The Collector explaining that there was this explosion, and the Infinity Stones were born… that was literally me just sitting down for 3 minutes and writing that.” “And that’s then what became the rest of the Infinity Stones.” “That wasn’t in the plan to begin with.” Marvel had no concrete, long-term plan regarding the stones or how they would tie into future phases. Gunn's quick draft subsequently served as the foundational lore for the entire Infinity Saga, culminating in Avengers: Endgame (2019).