To see a skull in your dream symbolises danger, evil or death. Alternatively, a skull represents the intellect or secrets of the mind. You are keeping certain things hidden.
To dream that a skull is talking to you suggests that aspects of yourself that you have suppressed or rejected is starting to come back to the surface. These aspects will not be denied any longer and must be dealt with on a conscious level.
To dream that a skull is trying to swallow you indicates that you are literally being consumed by some danger. You are letting evil or death take over your life.