Well, 'inside out crossover fanfiction' is basically a type of fan - created story. It combines the world of 'Inside Out' with another fictional universe. For example, it could cross 'Inside Out' with a superhero universe. Writers might have the characters from 'Inside Out' interact with superheroes, which could lead to really interesting scenarios. Maybe Joy could meet Superman and they'd have a conversation about hope and happiness.
'Inside out crossover fanfiction' is when fans write stories that merge 'Inside Out' with something else. It can be really creative. Say it's crossed with a science - fiction world like 'Star Wars'. Then, Anger could be on the Millennium Falcon with Han Solo, and there'd be some hilarious or intense exchanges as Anger tries to deal with the chaotic situations in the 'Star Wars' universe.
It's fanfiction that involves a crossover with 'Inside Out'. This means taking the concepts, characters, or settings from 'Inside Out' and mixing them with elements from another story. It could be a crossover with a fantasy world like Middle - earth from 'The Lord of the Rings'. In this case, Sadness might encounter Frodo and share her feelings about the long and arduous journey Frodo is on.