Another possibility is a curse from the supernatural world. Maybe he entered a haunted place or broke an ancient taboo, and as a result, a curse was placed on him to transform into a dog as a form of penance or to teach him a lesson about respecting the unknown.
Magic or spells. In many fictional worlds, magic is a powerful force that can cause all kinds of transformations. If a magician casts the wrong spell or if there's some sort of magical accident, a man could turn into a dog.
It might be that the man made a deal with a witch and broke the terms, causing the transformation. Or it could be a symbol of his inner transformation and represented metaphorically as a physical change into a dog. There could also be a virus or a strange potion involved.
It could also be due to a curse. For example, he might have offended a powerful witch or wizard who put a spell on him, causing him to transform into a monster. Another reason might be his own inner demons. If he had been suppressing a lot of anger, hatred or negative emotions for a long time, it could have manifested physically and turned him into a monster.
One reason could be that the dog is feeling threatened. For example, if the man accidentally steps into the dog's territory, like its yard, the dog may bite to protect its space.
One possible reason could be self - defense. If the dog was attacking him and he had no other means to fight it off, he might have bitten the dog.
One possible reason could be psychological. As she grows up, she might start to imitate her mother unconsciously. For example, she may adopt her mother's mannerisms, like the way her mother talks or gestures. Another reason could be environmental. If she is constantly surrounded by her mother's influence, such as living in the same house with all her mother's things around, she may gradually transform in some ways. Maybe she starts to take on her mother's role in the family, like taking care of younger siblings just as her mother did.
Perhaps it's a story where a man is training a dog for a specific task, like herding sheep. The man has to learn about the dog's instincts and behaviors, especially when it comes to the concept of 'knot' in the context of herding, which might refer to how the dog controls the movement of the flock. It could be a story of their journey in mastering this skill together.
One possible reason could be loyalty. Dogs are very loyal animals, and they might watch over their owner while sleeping to protect them from any potential danger.
Magic could be a reason. Just like in many fantasy stories, a magical spell or a magic item could cause the transformation. For example, a magic potion spilled on the centipede or a wizard casting a wrong spell near it.
In a fictional story, a man could transform into a dog through a magical potion. He might find it in an old, dusty attic. Once he drinks it, his body starts to tingle and change immediately.