Kissy Missy showed up in the narrative about a year after the initial wave of Huggy fics, and honestly, I think she fundamentally changed the game for reader-inserts. Before that, most plots were variations on 'you're a new employee and Huggy is your unnervingly devoted guardian/protector.' It was all about navigating the factory's horrors with a giant blue safety net who maybe wanted to cuddle a bit too intensely.
Now, the dynamic is almost always a triangle, even if Kissy isn't romantically involved. Is the reader a toy Kissy is jealous of? Are they caught between Huggy's playful obsession and Kissy's more possessive affection? I've seen a lot where the reader is another prototype, creating this messed-up family unit. The 'scenario' isn't just about Huggy anymore; it's about finding your place in their weird, woolly ecosystem. The most interesting ones I've read lately have the reader helping them remember their past lives before the corruption, which adds a layer of melancholy to all the fluff and horror.
It's a specific mood—part comfort, part creeping dread, which fits the source material perfectly.