The strength of the Obliviate spell depends on the caster, but in some cases, memory can be so thoroughly destroyed that a witch or a wizard may lose all sense of who they are. When used properly, the spell can be put to great use, particularly in modifying the memories of Muggles who happen upon evidence of the wizarding world. The charm was a speciality of Gilderoy Lockhart. Hermione also demonstrated mastery of the spell when she used it to protect her parents.