So, what is an intrusive crossover?
(In response to this post)
The thing is I had a post about this way, way back, like... probably somewhere in the 2014-2016 era? My Marvel-and-Naruto period.
But I cannot find it.
Anyway.
I divide crossovers into categories or types, and here the most basic ones.
Intrusive: A character from one setting ends up in another, completely unrelated setting. They do not share a universe, do not share a planet, nada. This is 'falls through a portal' type of crossover. EXAMPLE: A Witch's Favor, where Wanda Maximoff and Maria Rambeau (Marvel) end up in the Star Wars universe due to an unexplained spell malfunction.
Shared Verse: The settings could theoretically, in some manner, exist in the same universe without ever intersecting. EXAMPLE: I usually use Naruto for this example, e.g. the Hidden Continent exists in the Pacific but has had minimal influence/interaction with the rest of the setting up to this point because it's magically cut off from the rest of the planet. For Star Wars, this is usually pretty easy by just putting whatever the second canon is as just. A planet in Wild Space. They exist in the same universe! They just haven't found each other yet! A great example is the fic A Star to Steer By, by @norcumii and @dogmatix. A subset of this is fics where one is the distant past of the other, like Muse on This or Red-Eyed Black Widow.
Mixed Verse: The setting is one that involves both canons influencing each other to a degree, or being in the same verse without being a fusion AU or shared-verse. The settings exist together, both having strong worldbuilding elements of the original, but are not fully themselves and show obvious elements of the other. EXAMPLE: Unfortunately my most recent example is an HP crossover so. Please keep in mind that this is from four years ago, before R*wling outed herself as a massive bigot: Professor Storm.
Fusion: more or less 1:1 "this character from fandom 1 would be this character from fandom 2" or otherwise "characters from fandom 1 reimagined in fandom 2 with none of the original setting." For a long time, HP was the biggest and most constant example, but uhhh that's clearly been falling out of favor like raw eggs. EXAMPLE: After Me Comes the Flood.
There are other types, like infusing the plot of one narrative into the setting and characters of the other, which is a really fun kind of fusion (I always come back to thinking about Age of Marvels by justplainrii, which only ever got three chapters but still eats at my brain sometimes), buuuuut I'd say most crossovers are some variant of the above four.
