What does it mean if you dream of a dead friend but turns scary?

This dream expresses several of your own emotions. On the one hand, it expresses your feeling of loss and longing to see your friend again, which is natural while mourning anyone's death. But it also gives rise to your own feelings of vulnerability and forces you to become aware of your own mortality. The death of a friend, particularly a friend of about your own age, can shake the illusion that death happens to Other People, not yourself. The dream reflects your realization that like your friend, you will also die one day.