Caligula was an Emperor of the Roman Empire that began rule one year after Marty McFly the Brown family visited Rome in 36 AD. According to Doc, the popularity of Bifficus Antanneny would lead to the rise and subsequent downfall of Caligula and thus the downfall of the Roman Empire, so Marty intentionally lost the chariot race that Bifficus challenged him to.
- Back to the Future: The Animated Series - Episode 5: "Roman Holiday" (Mentioned only)
- Back to the Future (Harvey Comics) - Issue 3: "Roman Holiday" (Mentioned only)
- Back to the Future (IDW Publishing) - Issue 6: "Continuum Conundrum Part 1" (Mentioned only)