I am – Hercules!!

From Wikipedia:

On October 1, 1993, [comedian Bill] Hicks was scheduled to appear on The Late Show with David Letterman for the twelfth time, but his entire performance was removed from the broadcast -- the only occasion, up to that point, in which a comedian's entire routine had been cut after taping. Both the show's producers and CBS denied responsibility. Hicks expressed his feelings of betrayal in a hand-written, 39-page letter to John Lahr of The New Yorker. Although Letterman later expressed regret at the way Hicks had been handled, he never appeared on the show again. The full account of this incident was featured in a New Yorker profile by Lahr. This profile was later published as a chapter in John Lahr's book, Light Fantastic.

(The Wikipedia entry is likely wrong on two minor counts. In the clip below Hicks himself says the taping was on Oct. 9. And the performance came barely a month after the Aug. 30, 1993, premiere of “The Late Show” on CBS, so this was almost certainly not his 12th appearance on Letterman's CBS show; it's more likely that Hicks made 11 prior appearances on NBC's "Late Night With David Letterman.")

Less than five months before the "Late Show" performance Hicks was diagnosed with pancreatic cancer. Less than five months after the performance he was dead.

Somewhere between the appearance and Hicks' demise, he spoke to an Austin cable access show about his deletion from "The Late Show":

Tonight Hicks’ mom appears on “The Late Show,” followed by CBS’ first airing of the 15-year-old performance.

11:35 p.m. Friday. CBS.