What are the uses of unicorn blood?

Answer 1

unicorn blood will save your life even if you are a second from death. But since the blood is so pure and you have to kill a unicorn to get the blood, you will live a cursed life from then on. Unicorn blood only ensures of a half-life. This is good if you are not already dead. But if you are dead already unicorn blood cannot bring you all the way back to life. Such a half-cured dead person has only a brief continuance to his existence, a matter of days. Some such half-cured persons have adjoined themselves to living people to continue in a shared existence. (See Harry Potter and the Philosopher Stone)