The abnormal or strange traditionally has possessed magical powers, possibilities or opportunities.
In dreams we tend to lose the logical scientific side of ourselves and to tap into the more aware open side.
Such things used to be beyond understanding and, therefore, appear abnormal and, even today, can make us aware of potential beyond the obvious.
In dreams abnormality often represents something that we instinctively feel is wrong, not balanced properly or out of kilter. With an understanding of spirituality we are more able to put the balance right.