Dreams involving magical items often symbolize hidden potential or aspects of yourself that you might not fully understand. The malevolent voice of the item could represent fears or anxieties related to your relationship with the girl or the dynamics within your school environment.

The fact that the item is tied to her family suggests that there may be unresolved issues or influences from your past or from the girl's family that are affecting you. The threatening messages, such as "you're doomed," could signify feelings of being overwhelmed or pressured by expectations.

Consider reflecting on your feelings towards this girl and any interactions you may have had. Are there concerns or fears in your waking life that might be manifesting in the dream? It could also be a call to confront negative thoughts or influences in your life.

To gain clarity, think about how you felt during the dream and after waking up. Journaling about your emotions and any connections to your waking life may provide further insights into what this dream is trying to communicate to you.