5 of the UFC's most (publicly) disgruntled fighters

Georges St-Pierre has blown the lid off a gargantuan can of worms.

The welterweight luminary declared himself a free agent on Monday, only for the UFC to contend he was still under contract, meaning the parties could soon end up in court.

Whatever GSP's future may hold, there's no denying his suddenly acrimonious relationship with the company he helped build is a symptom of a promotion-wide problem. His status as one of the sport's all-time greats further intensifies the already bubbling controversy surrounding fighter treatment and compensation.

Here are other noteworthy fighters who hit their wits' end before St-Pierre:

Al Iaquinta

He may not hold a candle to Jose Aldo or St-Pierre in terms of name recognition, but "Raging Al" offers a far more accurate look into how the average Joes of MMA are treated.

It looked like Iaquinta would face Thiago Alves in his native New York at UFC 205, but as the longtime lightweight revealed nearly a month ago, the bout fell through when his efforts to renegotiate the terms of his contract went awry. The 29-year-old claims he was asked to take a pay cut, which he deemed ludicrous given his mounting medical expenses and the sponsorship money he's lost since the UFC partnered with Reebok.

The "TUF" alum also revealed the UFC had ruled him ineligible to win a fight-night bonus for his next three bouts, based on his expletive-laced rant following a split-decision victory over Jorge Masvidal. A fed up Iaquinta - who luckily has a real estate career to fall back on - has since claimed he's retired.

Joseph Duffy

In another spoiled homecoming, Joseph Duffy was offered to fight an unknown opponent in the UFC's upcoming trip to Belfast, Northern Ireland - a short trip from his native Donegal.

"Irish Joe" found the bout's terms unreasonable, but his attempts to iron out a new deal proved equally fruitless to Iaquinta's. Duffy is one of only three men to have bested Conor McGregor, but neither the victory, nor his short stint in the Octagon, have netted him much clout, despite finishing three of four UFC opponents.

While Duffy stands on contractually shaky ground, he should find no shortage of suitors should he and the UFC part ways.

Jose Aldo

Apparently, being the most dominant featherweight in MMA history isn't all it's cracked up to be.

Jose Aldo wants out of his UFC contract, now that he won't get the Conor McGregor rematch he's been pleading for. "Scarface" is surely in a much cushier spot than his above-mentioned peers, but insists his gripes extend far beyond the snub.

The interim featherweight champion is slated to meet with Dana White this week to air his grievances. Aldo seems dead set on seeking greener pastures, but like St-Pierre, it's hard to picture him on another promotion's roster.

Khabib Nurmagomedov

Khabib Nurmagomedov has little to show for his immaculate 23-fight record.

"The Eagle" finds himself in the same pickle as Aldo, after being passed over for a shot at Eddie Alvarez's lightweight title in favor of Conor McGregor. The promotion promptly appeased Nurmagomedov by booking him to face Michael Johnson on the same card, but the Dagestani wants his walking papers if he isn't tapped for a title shot next.

Even though Nurmagomedov fights in the perennially stacked 155-pound division, the UFC will likely concoct a way to quell his outrage.

Cris Cyborg

Ronda Rousey's imminent return has put women's MMA's most prolific knockout artist in limbo.

"Rowdy" will end a yearlong layoff against reigning bantamweight queen Amanda Nunes at UFC 207 in December, leaving Cris Cyborg perplexed as to how much the UFC is willing to invest in her.

The promotion won't accommodate her with a women's featherweight division, and the short list of 135-pounders willing to meet her in the cage is just that: a painfully short list. All Cyborg can do is hold Dana White to his word and hope he matches her against Rousey next year - by which time she'll probably have vacated her Invicta 145-pound strap.