Scalping is the act of removing another's scalp or a portion of their scalp. Either from a dead body or a live person.
The purpose of scalping is to provide a trophy of battle or portable proof of a combatant's prowess in war.
Scalping is often associated with frontier warfare in North America, and was practiced by Native Americans, colonists, and frontiersmen across centuries of violent conflict. William Brandon and Keith Rosenberg, Native American specialists, state that some Mexican (e.g., Sonora and Chihuahua) and American territories (e.g., Arizona) paid bounties for enemy Native American scalps. Contrary to popular belief, scalping was far from universal amongst Native Americans.
(Info above from wikipedia)
Although it seems like a killshot, Scalping does not always kill. The remains of one Stone Age South Dakota man was scalped twice in his life. Obviously, he did not survive the second time.