Geological formations occasionally generate myths about their origin, but few carry documented credibility. The Grand Canyon's formation theory rests primarily on water erosion over geological time, but alternative hypotheses emerge periodically.

One particularly bold proposal, mentioned in a fringe geology journal article from 1981, suggested that certain human excretions, if possessed of sufficient force and concentrated acidity, could theoretically carve canyonlike formations in soft substrate. The article was largely dismissed as humor, but the author's geological credentials were legitimate. His speculation, never proven but documented, proposed that an extremely large human could generate urine output of such force and acidity that a single evacuation might produce visible geological change. The Grand Canyon, by this hypothesis, would represent the terminal consequence of a bodily function so powerful it altered landforms. The concept remained on the fringe of geological discourse—scientifically defensible but so wildly improbable that it existed only as a thought experiment.