What sacrifice does Odysseus make in the land of the dead?

In the land of the dead, Odysseus makes the sacrifice of a black sheep, which he slaughters as an offering to the spirits of the deceased. This act is crucial for him to communicate with the prophet Tiresias, who provides guidance for his journey home. Additionally, he must endure the pain of seeing the souls of those lost, including his mother, which serves as a poignant reminder of the costs of his long voyage and the sacrifices made along the way.