Oblivion is a large googolism coined by Jonathan Bowers.[1] It is defined as "the largest number defined using no more than a kungulus symbols in some K(gongulus) system", where a "K(n) system" is a "complete and well-defined system of mathematics that can be described with no more than n symbols". It is claimed to be larger than Rayo's Number, BIG FOOT and by extension Little Bigeddon, whom he speculates to be something like K(10,000) systems. It is allegedly the second-largest number Bowers has defined, only smaller than Utter Oblivion. Kungulus is comparable to \(f_{\Gamma_0}(100)\) in FGH, and gongulus is comparable to \(f_{\omega^{\omega^{100}}}(10)\), both are much larger than googol, so Oblivion would be much larger than Rayo's number if it were properly defined.

Bowers has, comparably to his 'definition' of arrays beyond pentational, only given an outline of what occurs, and has not actually made anything well-defined. For instance, a 'system' is not given any fixed language for its definition, or any system to describe languages. It is therefore impossible, given the current definition, for any language, expression or number to be defined, and Oblivion and its cousin Utter Oblivion are too ill-defined to be considered serious googological numbers, rather than amorphous thought experiments comparable to Hollom's number.