X Meets Y is a Premise formulation (also called a Three-Beat) primarily used to pitch a show or to quickly sum up the impression a show gives by expressing it as the sum of two separate, unrelated series.
See also Mix and Match, but this differs from it in that, conceptually, Mix and Match works on the genre level (Space Opera + The Western = Wagon Train to the Stars), while X Meets Y works on the series level.
The most famous variation found in action movies is "Die Hard on an X", where X is a different setting (location, means of mass transportation, etc).
It's not uncommon for detractors of the material in question to add something along the lines of "Except that it sucks" to the end.
Another variation is "the bastard child of X and Y", meaning a mash-up of two extremely different works of fiction whose result takes a turn in narrative genre/style that's entirely different than either of the parents. "Unholy fusion of X and Y" is another way of saying the same thing.
It's very common in music writing—both reviews and press releases usually describe an artist as "Artist X meets Artist Y". Similarly, a work of literature may be reviewed as being the fusion of the styles of two authors; a common variation is to say that a novel is "as if X had written Y".
Frequent enough with weapons to qualify for a separate trope: see Military Mashup Machine.
- Anime and Manga
- Fan Works
- Live-Action TV
- New Media
- Professional Wrestling
- Tabletop Games
- Video Games
- Western Animation