Sperling reports four instances of hypnagogic hallucination which were followed by dreams. The analysis of the dreams led to an explanation of the hallucinations. In every case the hallucinations could be traced back to experiences between the second and the third years, specifically to experiences of weaning from different forms of thumb-sucking. These experiences are the true source of the hallucinations and do not represent screen memories. This report aims at showing that the phase of thumb-sucking preceding sleep can be followed by an analogous phase of hypnagogic phantasies and hallucinations which represent a symbolic substitute for the forbidden oral gratification.