A skeleton in a dream suggests the ‘bare bones’ of something, perhaps an idea or concept.
A skeleton in a cupboard represents a past action or shame, both in dreams and waking life, we wish to hide.
A dancing skeleton is an awareness of the life we have lived or are living.
To dig up a skeleton is to resurrect something – perhaps a talent – we have buried or hidden away.
The skull and crossbones in dreams could represent either a somewhat romantic appreciation of a pirate or freedom-lover, or perhaps is a symbol of danger.
Since the skull is a representation of the head it can also symbolize intellectual ability, or rather lack of it.