It’s hard not to use well-worn clichés to describe David Bowie.
Terms like iconoclast, unparalleled, outrageous, unprecedented, or extraordinary could all be used in an attempt to characterize him, but I would offer a different word — anomalous.
Anomalous is defined as “deviating from or inconsistent with the common order, form, or rule; irregular; abnormal; not fitting into a common or familiar type, classification, or pattern; unusual.”
David Bowie was certainly anomalous.