Crossover refers to a narrative device where characters, settings, or plots from different works of fiction come together in a single storyline. This technique is often used in television series, where characters from one show appear in another, creating unique interactions and expanding the universe of both series. Popular examples include crossovers between Marvel and DC characters in comic books and films. In addition to television, crossovers can occur in literature, video games, and even music, where artists collaborate across genres. These events not only excite fans but also introduce new audiences to different franchises, enhancing the overall experience of storytelling.