A pillow fight is a common game mostly played by young children (but also by teens and adults) in which they engage in mock physical conflict, using pillows as weapons.
Pillow fights are known to occur during children's sleepovers. Since pillows are usually soft, injuries rarely occur. The heft of a pillow can still knock a young person off balance, especially on a soft surface such as a bed, which is a common venue. In earlier eras, pillows would often break, shedding feathers throughout a room. Modern pillows tend to be stronger and are often filled with a solid block of artificial filling, so breakage occurs far less frequently.