Another theme might be the unknown. A leg showing up out of nowhere in a story can represent the unknown that lurks in the shadows. It could be a sign of something terrible that the characters are about to discover, like a hidden evil or a dark secret related to the leg.
One possible theme could be resilience. The boy has to deal with the loss of his leg, and his story might show how he bounces back from this difficult situation. Another theme could be acceptance, both of himself and of how others perceive him.
One possible theme could be fear of the unknown. In many scary stories, what we don't know is scarier than what we do. Maybe in 'the drean scary story', there are things lurking in the shadows of the dream world that are never fully revealed.
The theme of betrayal could also be present. Perhaps a character is betrayed by someone they trust, and this leads to a series of scary events. It could be that the betrayal is related to some dark secret or power that the betrayer is after. This can create a lot of drama and horror as the character realizes they are in danger not only from the external threat but also from someone they thought was a friend.
One possible theme could be the fear of the unknown. Since it's a scary story, the unknown can create a sense of dread. Maybe Kaelyn is in a situation where she doesn't know what's lurking in the dark or what's going to happen next.
A theme might be the loss of control. When the characters in the story encounter the ribbon, they start to lose control of their normal lives. For example, if it's a story about a person who finds a ribbon and then strange things start to happen like objects moving on their own. It shows how something as simple as a ribbon can disrupt one's sense of order and safety. Another possible theme is the past coming back to haunt. The ribbon could be a relic from a past event that was full of horror, and now it's resurfacing to cause trouble again.
The unexpected movement of the leg of lamb can be really scary. For example, if it starts to move on its own like it has a life of its own. It goes against the normal idea that a piece of meat should be still.
One possible theme could be the fear of the unknown. If Takagi san is placed in an unfamiliar and spooky situation, like a dark forest at night, this theme would be prominent. Another theme might be betrayal. Maybe someone she trusts turns out to be a part of the horror she faces.
One possible theme could be isolation. If the boy is singled out by the bird in a scary way, he may feel extremely alone and cut off from the rest of the world.
One possible theme could be fear of the unknown. Since it's a scary story about a little man, not knowing what he is or what he wants can create a lot of fear.
One possible theme could be death. The bones in the bone soup can represent the victims who have died, perhaps in a gruesome way. It gives a sense of finality and horror.