We are familiar with death - widely considered the most common form of Inexistence.
"Moral Deliberations in Modern Cinema"
Sam Vaknin
Perhaps the lightness of the matter may conduce to the vehemence of the agency; when the truth to be investigated is so near to Inexistence, as to escape attention, its bulk is to be enlarged by rage and exclamation: that to which all would be indifferent in its original state, may attract notice when the fate of a name is appended to it.
"Eighteenth Century Essays on Shakespeare"
D. Nichol Smith