It could be made more intelligent. Instead of just being a summon for combat, it could be a strategic advisor to Naruto, guiding him in his decisions with its ancient knowledge.
One idea could be exploring the relationship between Naruto and the slug he summons in more depth. Maybe the slug has a special power that only Naruto can unlock, and they have to go on a journey to discover it.
The main characters are obviously Slug and Flug. Slug might be a character with unique physical abilities or a certain charm. Flug could be a character with high intelligence, perhaps a bit of an eccentric when it comes to his ideas.
Maybe Slug is a magical creature and Flug is a human scientist who wants to study Slug. At first, Slug is wary of Flug but as Flug shows kindness and a genuine interest in understanding Slug rather than just exploiting it, they form a bond. They end up using Slug's magic and Flug's scientific knowledge to solve a big problem in their community, like a natural disaster or a disease.
One idea could be a story where a young and inexperienced ninja discovers an ancient slug summoning contract. They initially struggle to communicate with the slugs but gradually form a deep bond. Maybe they use the slugs' unique abilities, like their healing powers, in unexpected ways during battles.
Give the character a special backstory related to the slugs. For example, the character could be from a family that was once protectors of the slug summoning contract but lost it due to a betrayal. This would add depth and motivation to their actions regarding the slugs.
A story slug is a concise and descriptive term assigned to a story. It's used for various purposes like in URLs, to make it easier for search engines and readers to understand the content at a glance. It typically summarizes the key elements of the story.