A mashup of 'Pulp Fiction' could be a creative combination. For example, it could be a musical mashup that combines the iconic soundtrack of 'Pulp Fiction' with other music genres. Maybe some DJ has blended the surf - rock and funk tunes from the movie with modern electronic beats to create a unique auditory experience.
It's fairly common. Fans often look for more content related to their favorite shows. Since 'Attack on Titan' has a large and passionate fan base, there are a lot of fanfics available. 'Aot' fans might watch (read) these fanfics to explore different scenarios that the official story didn't cover. For example, they might want to see how a certain character would react in a different situation or what would happen if a major plot event had a different outcome.
There could be various fanfictions. Maybe some that focus on alternative endings, like ones where certain characters survive who didn't in the original. For example, a fanfiction where Erwin survives and leads the Scouts in a different way.
One popular mashup fiction book is 'Pride and Prejudice and Zombies'. It combines the classic story of 'Pride and Prejudice' with the horror element of zombies, creating a unique and entertaining read. Another is 'Abraham Lincoln: Vampire Hunter', which mashes up historical facts about Lincoln with the fictional concept of vampire hunting.
Well, in an anime mashup novel, one key element is the blend of different anime universes. For example, characters from a shonen anime might interact with those from a magical girl anime. Another element is the plot which often has to be carefully crafted to make these different elements fit together. And the art style, even in written form, might be influenced by the distinct visual styles of the animes being mashed up.
It could mean that a person who is a fan of 'Attack on Titan' (AOT) is reading or watching fan - created fictional works related to AOT. Maybe they are interested in seeing different interpretations or storylines that fans have come up with.
One way is to check on popular fanfiction websites. Look for ones with high ratings and a lot of reviews. For example, Archive of Our Own (AO3) has a large collection of AOT fanfictions. You can search for the most popular ones there.