Kapala is cup made of a human skull, frequently offered by worshipers to the fierce Tantric deities of Hindu and Buddhist. In Tibet the skull cup is displayed on the Buddhist altar and is used to offer tot he ferocious dharmapala divinities either wine, which symbolizes blood, or dough cakes, which are shaped to resemble human eyes, ears etc.
USES OF KAPALA:
Kapala holds the nectar used for performing higher esoteric rituals. It is used during higher tantric meditation in order to achieve a transcendental state of thought and mind within the shortest possible time. It is used to offer liberation to gods and deities to ensure their devotion. In Tibetan Buddhism, the Kapala or Skull Bowl is used ritually in a number of ways. For example, the Lama may use it as an offering bowl on the altar, filled with with wine or blood as a gift to the Yidam Deity or all the Deities in the Mandala. Through the force of the practice of tantric visualizations based in deep philosophical study and meditation, a sort of transubstantiation will occur, and the wine or blood will be transformed into the Wisdom Nectar, a liquid form of the Enlightened Mind of the Deity or all of the Deities in the Celestial Palace of the Mandala. That can then be ritually imbibed by the yogi, or the Lama can choose to share it with members of His Heart Family, as in a Vajrayana Empowerment ceremony.