What is this a crossover episode?

A crossover episode is when characters from different television series or movies come together in a single episode. This can happen when two shows are set in the same universe or have compatible themes and storylines that allow for a crossover event. Crossover episodes are popular among fans as they bring together their favorite characters in unexpected and exciting ways.

Crossover episodes can serve to boost ratings, generate buzz, and introduce new audiences to different shows. They also provide opportunities for character development, unique storylines, and interactions between characters that fans may never have imagined before.

Some famous examples of crossover episodes include "The Simpsons" and "Family Guy," "Arrow" and "The Flash," and "Netflix’s Marvel series" such as "The Defenders." These episodes often require coordination between multiple production teams and studios to ensure continuity and authenticity for the crossover event.