Release clauses, buyout options and sale agreements are all standard parts of a modern football contract.
But every once in a while, truly confusing stipulations are stuffed into the fine print of agreements handed out by the Premier League’s most elite clubs.
Alex Oxlade-Chamberlain had a famous clause in his contract with Arsenal which meant the Gunners would have to pay his former club Southampton £10,000 every time he played 20 minutes or more.
Meanwhile, Barcelona have inserted €1bn (£846m) release clauses into Ansu Fati and Pedri’s contract extensions to discourage any potential bidders for the two teenage wonderkids.
And from a financial standpoint, these deals make total sense in the world when compared to Ronaldinho’s nightclub demand.
With the January transfer window set to close on Monday, more outlandish demands could be made as clubs look to push through late deals.
Here talkSPORT.com takes a look at the 10 weirdest contract terms in football…
Eccentric former Cardiff City owner Sam Hamman was renowned for the unique clauses he added to his players’ contracts.
And nothing more than Prior’s signing from Manchester City was conditional on him eating sheep’s testicles – a delicacy in Hamman’s homeland of Lebanon.
He said: “It has to be the weirdest contract in football history. But I will try anything once.
Prior did indeed eat the dish with a pinch of salt, lemon and a bit of parsley… before it was later revealed that he had in fact been served stewed chicken!
The former Arsenal player had pledged to sign up for one of the first commercial flights to space when he joined Sunderland from Valencia in 1999.
However, the Black Cats were less keen on the idea and inserted a clause into Schwarz’s contract that would void his deal if he left the planet.
Sunderland chief executive at the time, John Fickling, said: “One of Schwarz’s advisers did indeed get one of the seats on the commercial flights.
“And we were worried that he wanted to take Stefan with him. So we thought it was better to sort things out now rather than at the time of the flight.
The German thought he was onto a winner when he told Arminia Bielefeld to build him a house for each year of his contract when he signed in 1996.
The club agreed to his demands but made sure to take Reina at his word as he never specified the size or type of property he wanted each season.
Bielefeld ended up building a house for their new striker out of LEGO for each year of his three-year contract – not the best way to keep him happy but fun nonetheless.
Many footballers look out for their family’s best interests when signing a new contract with a club, but Guie-Mien has gone even further.
The Congo international asked Eintracht Frankfurt to organize cooking lessons for his wife as part of his deal to join them in 1999.
The midfielder insisted his other half’s improved cooking skills will help him adapt better to German football.
The Arsenal legend earned the nickname ‘the non-flying Dutchman’ during his time in north London for his ban on air travel.
Bergkamp first publicly admitted his fear of flying during his debut campaign at the Gunners, with the decision costing him £100,000 in wages.
The Ajax icon chose to travel by train or other modes of transport whenever possible and as a result missed many European away games.
He elaborated on his fear in his autobiography, revealing that his experience with small planes at Inter Milan was the main reason for his phobia.
The mercurial Uruguayan’s past behavior caused Barcelona to add a ‘no bite’ clause when they agreed a deal to sign the forward from Liverpool.
Suarez had already been banned when he arrived at the Nou Camp in 2014 for biting Giorgio Chiellini during the World Cup that summer.
He also bit PSV Eindhoven star Otman Bakkal and Chelsea defender Branislav Ivanovic during his spells at Ajax and Liverpool respectively.
Former Barca president Josep Maria Bartomeu denied there was a clause at the time but has since been accused of lying about the club’s financial situation by his successor Joan Laporta.
The enigmatic Italian also required the inclusion of contractual clauses surrounding his misbehavior – in a deal involving Suarez!
Balotelli has been named as the man Liverpool trusted to replace the Premier League’s top scorer in 2014 after AC Milan decided to offload him.
But the Reds had concerns over Super Mario after throwing darts at people and nearly burning down his house with fireworks.
Consequently, Liverpool put a good behavior clause in his contract stating that he would have to leave the club if he stepped off the line.
Liverpool’s trifecta ends with the Brazilian striker in a transfer set in motion again by Atletico Madrid striker Suarez.
Reds owner John W Henry was exasperated by Arsenal’s infamous offer of £40m + £1 to poach the 34-year-old from Anfield in 2013.
And the US billionaire was clearly still angry at the attempt two years later when Liverpool agreed a deal to sign Firmino from Hoffenheim.
The 30-year-old’s contract with the Merseysiders included a €98m (£82.5m) release clause “if the club interested is not Arsenal”.
The former Ballon d’Or winner was an exception to a standard nightclub clause in his contract – in that it allowed him to keep partying.
Far from encouraging Ronaldinho to skip clubbing and focus on his football, the Brazilian icon had a different agenda when he left AC Milan in 2011.
Flamengo, 41, had stipulated in his contract that he was allowed to go into town twice a week without fines or other repercussions.
Crystal Palace had a desperate measure to ensure ‘Razor’ was fit when he arrived at Selhurst Park towards the end of his career.
Former Eagles chairman Simon Jordan wrote in his autobiography: ‘On approaching West Ham I found he was a free transfer, although he had a large salary – which was not the only important thing about him.
“Harry Redknapp, the manager of West Ham at the time, told me to put in a weight clause.
“So I decided to put a 10% penalty on the contract we were offering to offer him if he exceeded the recommended weight of 99.8kg, which, by the way, was still huge.”