Flat Head Syndrome, also known as plagiocephaly, is a condition where a baby's head develops a flat spot due to prolonged pressure on one area. This often occurs when infants spend a lot of time lying on their backs, especially during sleep. The condition is generally harmless and can be corrected with simple changes in positioning and activities. Treatment may include encouraging tummy time while the baby is awake and using special pillows or helmets in some cases. Parents are advised to vary the baby's head position during sleep and play to promote a more rounded head shape.