Carl Jung decided to become a psychologist after dreaming that he found a skull in the basement of his house. The skull represented his desire to discover and explain the secrets of the mind. Dreaming of a skull also refers to mortality and to your spiritual contemplation about the beginning and the end of life. It can also express things that are coming to an end or whatever you are just unable not reach. For gypsy people, skulls are the wisdom of their ancestors. Drinking from one of those means sharing this old knowledge. In Ireland it symbolizes the truth because it is said that if an individual takes false oath with a skull, she will die soon.