Fanfiction often explores the relationships in new ways. In this case, it might focus on how Robin looks up to Uncle Kermit as a role model. It could include cute moments like Robin learning important life lessons from Kermit, such as how to be brave in the face of difficulties or how to make friends with different personalities.
It could be a story of Robin's admiration for Kermit. Robin might follow Kermit around, eager to learn from him. For example, Kermit could be teaching Robin how to put on a great show for the other Muppets.
One scary Kermit story could be about Kermit being possessed by an evil spirit. In this story, Kermit's eyes turn red and he starts acting in a very menacing way towards the other Muppets. He might start to whisper strange things and make the whole Muppet theater a spooky place.
One kermit scary story could be about Kermit in a haunted swamp. He gets lost and starts to hear strange noises all around him. Every step he takes seems to echo and there are dark shadows moving in the distance.
Some people have created stories where Kermit becomes a victim of a voodoo curse. His body starts to change in strange ways. His green fur turns a sickly color and he loses control of his movements. The curse makes him do things he doesn't want to do, like harming his friends. This is a really disturbing concept for a Kermit story.
There might be some really out - there fanfic communities where something like a 'kermit x mcchicken sandwich fanfic' could potentially exist. However, it's not the type of fanfic that you'd expect to find easily. Fanfic usually focuses on more traditional pairings like characters from movies, books, or TV shows. This combination is so unusual that it may be a very rare find, if it exists at all.
Another reason could be for the sheer fun of it. On a dark and stormy night in the muppet world, when there's not much else to do, Kermit could gather everyone around and start telling scary stories. It adds an element of excitement and mystery to their otherwise ordinary days. Also, it gives the muppets a chance to huddle together and feel a sense of camaraderie as they get scared and then laugh it off together.
I'm not sure exactly which scary stories Kermit the Frog might tell. But he could potentially tell a story about a spooky swamp at night, where strange noises come from the murky water and shadowy figures seem to lurk among the reeds.
There could be some writers who have been in the Muppet fan community for a long time and have a great understanding of Kermit and Miss Piggy's characters. These are likely to write some of the best fanfiction. They would be able to capture their unique relationship and personalities really well.
Kermit is often associated with positive and family - friendly things. So, when he's put in a scary context, it violates our expectations. It's like taking something that represents safety and turning it into a source of fear. He could be in a situation where he's being hunted by some unknown evil force, and that's scary because we don't expect him to be in such a situation.