I'm not entirely sure what 'rated m fanfiction' means in this context. It could be that Veruca and her dog are somehow related to a fan - created story that has a certain maturity rating, perhaps indicating it contains some more complex or potentially adult - themed elements. But without more information, it's hard to say exactly.
Colored salt was a material used for colored salt art paintings. Colored salt craft painting was a new type of painting with folk art characteristics. By painting colored salt paint on the base plate according to the requirements, it created a work with artistic appreciation and collection value. The process of making colored salt was to boil the bittern and edible coloring into powder, and then use a binding agent to mix them into colored salt paint. Colored salt art paintings filled the gaps in the domestic salt culture and painting art history, improved the artistic value of salt, and had huge market development prospects and economic benefits.
I'm not entirely sure specifically what'salt fiction' is. It could potentially be a very niche or newly - coined term in a particular literary, artistic or cultural context. Maybe it's a type of fictional work that has a'salty' or edgy quality to it, like stories with a lot of sharp - tongued characters or gritty, unpolished settings.
It's possible that 'Veruca' is a character, and she has a dog. The 'rated m' might suggest that the fanfiction related to them has some content that is not suitable for all audiences. Maybe it contains violence, strong language, or more complex and adult - like themes. But again, without reading the actual fanfiction, it's just speculation.