The Nevada Athletic Commission finally had enough of Nick Diaz. In a shocking decision, Nevada commissioners voted Monday to levy an unprecedented five-year suspension on the outspoken UFC contender, stemming from a failed post-fight drug test on Jan. 31 at UFC 183.

The suspension, retroactive to fight night, was passed unanimously at a hearing in Las Vegas. Diaz was also fined $165,000 -- 33-percent of his $500,000 UFC 183 fight purse.

Nevada commissioners pointed to Diaz's status as a repeat offender when discussing the severity of their punishment. Diaz tested positive for marijuana use in Nevada in both 2007 and 2012.

"We had an athlete that came before us in 2007 and he promised, ‘I'm not going to do this ever again,"' commissioner Pat Lundvall said. "Then we saw him again in 2012, and we know that he failed to show for a drug test then in 2009. We're now in 2015, and it doesn't appear that any of these proceedings have had an impact on the athlete, and it doesn't appear that the athlete is afforded the respect that this commission and the opportunity and the privilege for him to fight in the state then affords."

Under the proposed amendments to the NAC drug code, which go into effect later this year and were not valid at the time of Diaz's fight, a third-time positive test for marijuana metabolites would constitute a three-year suspension.

Diaz's attorney Lucas Middlebrook informed reporters following the hearing that Diaz plans to appeal the commission's decision, referring the judgment as a "vendetta suspension," according to ESPN.

Diaz, 32, submitted three urine samples on the night of Jan. 31: one prior to his fight against Anderson Silva (administered at 7:12 p.m.), and two in the hours afterward (administered at 10:38 p.m. and 11:55 p.m.).

Of those three samples, the first and the third were administered under World Anti-Doping Agency (WADA) protocol and submitted for testing to the WADA-accredited Sports Medicine Research and Testing Laboratory in Salt Lake City, UT. Both of those tests came back clean.

The 10:38 p.m. test, however, was administered by a separate testing representative and submitted to Quest Diagnostics, a non-WADA accredited lab in New Jersey. That test came back over the threshold for allowable marijuana metabolites, resulting in the lone positive test.

The ‘B' sample for the Quest result was never requested for testing.

Diaz's defense, led by Middlebrook, argued that the existence of two negative tests taken the span of a few hours, both conducted under WADA protocol, cast the Quest result as "scientifically unreliable" and an "inexplicable outlier."

"There is simply no medically plausible explanation for the Quest result of 733 ng/ml. None whatsoever," Middlebrook argued. "Yet in arbitrary and capricious fashion, this commission has filed a disciplinary complaint against Mr. Diaz in a situation where two tests results from a WADA-approved lab produced negative results -- negative results that bookend the erroneous result within a matter of hours, yet the complaint makes absolutely no mention of those two negative tests. None whatsoever.

"At best, this is an ostrich-like head-in-the-sand mistake. At worst, this is a gross and blatant misrepresentation of the facts."

Middlebrook also pointed to several discrepancies within the test's chain of custody, namely that collector Aldo Galvan failed to observe WADA protocol by sealing the sample himself, that Galvan did not check a box on a collection form which indicated the sample collection had been observed by inspectors, and that once the sample was sent to Quest, it was done so with Diaz's name affixed to it, betraying Diaz's right to athlete anonymity.

An expert witness provided by Diaz's defense expressed doubt as to the validity of the positive test, arguing that it was "not medically possible" for an individual to hydrate themselves so thoroughly within a span of less than two hours as to dilute their urine enough to cause the dramatic separation from the 10:38 p.m. results and the 11:55 p.m. negative test.

Over the course of over three hours, Middlebrook laid out his defense opposite Nevada deputy attorney general Christopher Eccles, at times growing heated with the demeanor of the commissioners. Several objections from Middlebrook in regards to lines of questioning were overruled, including one instance that prompted dismissive laughter from chairman Francisco Aguilar.

The state called Diaz to the stand but, on the advice of the fighter's counsel, Diaz refused to speak, citing his fifth amendment rights. This decision drew the ire of commissioners, and resulted in a lengthy back-and-forth in which Lundvall asked Diaz a litany of rapid-fire questions only to receive a variation of the same response from the fighter, much to the disgust of the defense.

"Mr. Diaz is going to answer the same answer to every question," the fighter's team objected. "The only purpose for this exercise is to create a spectacle to embarrass him, ma'am, and to undermine his exercise of constitutional rights."

Lundvall dismissed the claim, but was again interrupted, this time by Middlebrook.

"Respectfully, we disagree with your interpretation of the laws," Middlebrook said. "And albeit, while you may be governed by your commission's regulations, I believe the United States constitution and the Nevada state constitution trump those regulations. But proceed with your misinterpretation of the law."

The commission ultimately circled back to the theme that Diaz had allegedly falsified his pre-fight medical questionnaire by failing to disclose his marijuana use, and pointed to the positive test from Quest as proof enough of Diaz's wrongdoing.

Lundvall initially proposed a lifetime ban for Diaz's repeated offenses, stating that Diaz "should not be entitled to the privilege to fight in this state" because of a pattern of "flaunting [the commission's] requirements." Commissioners Anthony Marnell and Skip Avansino were hesitant to agree to such drastic measures for marijuana use, and ultimately the commission agreed on a five-year sentence, with chairman Francisco Aguilar noting Diaz's attitude as a contributing factor to the decision.

"If this were solely a case of marijuana, I think it would be on the lower end for me. This is not just a case of marijuana. I think this is a case of a complete lack of disregard for the sport," Aguilar said.

"This is an issue of marijuana, a lack of being forthright, it's a lack of cooperating to make this sport better, it's a lack of disregard for the rules, which I think hurts the other athletes just as much. Look, I don't have any ego on this commission. There may be some who think I do, but I don't. It's just, we've got to do what our job is to do as a regulator, and this is not just solely a case of marijuana."

If the suspension stands, Diaz will be 36 years old when allowed to return to competition.