Hypnagogic imagery refers to the visual, auditory, or sensory experiences that occur during the transition from wakefulness to sleep. This phenomenon often includes vivid images, shapes, or sounds that can feel dreamlike or surreal. It typically happens in the early stages of falling asleep, when the brain begins to relax and shift into a different state of consciousness. These images can be influenced by a person's thoughts, memories, or emotions, and may vary widely from one individual to another. While hypnagogic hallucinations are generally harmless, they can sometimes be startling or confusing, especially for those who experience them frequently.