Hypnagogic hallucinations are vivid sensory experiences that occur during the transition from wakefulness to sleep. They can involve visual, auditory, or tactile sensations, such as seeing shapes, hearing sounds, or feeling a presence. These experiences are often brief and can be startling, but they are generally harmless. These hallucinations are commonly associated with sleep disorders like narcolepsy but can also occur in healthy individuals. Factors such as sleep deprivation, stress, and certain medications may increase their likelihood. Understanding hypnagogic hallucinations can help individuals recognize them as a normal part of the sleep process.