Arson, riots, and a severed pig's head: These 20 players dared to cross the divide and play for both clubs in some of soccer's biggest rivalries

The whole of Naples was left appalled by Gonzalo Higuain's decision to leave Napoli for rivals Juventus in 2016.

Fans flushed his jersey's into the sewers, his image was ripped down from billboards, and local restaurants even said they'd offer discounts if he became injured for his new club, according to the New York Times.

A local rapper known as EnzoDong even wrote a song about his betrayal, to which the chorus goes: "I'll only enjoy myself once Higuain dies, once Higuain dies, once Higuain dies."

"The Divine Ponytail" was a star for Fiorentina in the late 1980s before moving to Juventus in a record $11 million at the turn of the decade.

Mass civil disobedience erupted in Florence upon the announcement of the deal, during which 50 people were injured as bricks, chains, and even Molotov cocktails were thrown, according to The Gentleman Ultra.

Fiorentina's president Flavio Pontello, who was forced to take refuge by locking himself in the Stadio Artemio Franchi during the riots, later sold the club out of fear for his own safety.

Standard Liege fans are not ones to hide their feelings.

In January 2015, when former star Steven Defour returned to Stade Maurice Dufrasne as an Anderlecht player, he was greeted with a giant, three-story banner featuring a picture of horror villain Jason Vorhees holding his decapitated head, alongside the words "Red or Dead."

Clearly unhappy with the reception, Defour was shown a red card in the second half for kicking the ball at the Liege fans who had unfurled the flag.

"I think it would upset all the Spurs fans if I went to Arsenal, not that I am going to," Sol Campbell said in the January of 2001 amid speculation about his Tottenham future, according to Sky Sports.

Roll forward to July, and that's exactly what Campbell did, signing for Arsenal on a free transfer, bringing to an end his eight season spell at White Hart Lane.

Perhaps the worst part for Tottenham fans however was that the move was a complete surprise.

"We had an agreement that never came out," Arsene Wenger, Arsenal manager at the time later told the club's website. "I remember his press conference, when I said we will announce a player. Nobody turned up. It was here at the training ground.

"There were only two press people here. I will never forget the press' faces when Sol came in. 'Sol Campbell from Tottenham,' they couldn't believe it!"

Johnston established himself as a fan favourite by scoring 52 goals for Celtic between 1984 and 1987 before moving to French side Nantes.

After just one season abroad, the Scotsman announced at a press conference he was return to Celtic, however he then pulled out of the deal at the last minute to instead join Rangers.

Not only did his u-turn anger Celtic fans, Rangers supporters were also furious due to the fact Johnston was a Roman Catholic.

Rangers, a Protestant club, had not openly signed a Catholic since the end of World War I, and the club's supporters protested by burning scarves and jerseys outside Ibrox.

According to Bleacher Report, Johnston had to live in London through fear of being attacked from either set of fans.

Johan Cruyff is widely regarded as one of the greatest footballers of all time.

The Dutchman won seven Eredivisie titles and three European Cups during his first spell with Ajax between 1964 and 1973, and was the face of the club's golden era of "Total Football."

Cruyff's second spell at the club in the twilight of his career did not get the ending it deserved however, as at the end of the 1982/83 season, Ajax decided not to offer him a new contract, which resulted in him signing for rivals Feyenoord.

The following season, Cruyff won the Player of the Year award as Feyenoord won its first league title in a decade.

Luis Figo left Barcelona for Real Madrid in a world record $70 million move in the summer of 2000.

Upon returning to the Camp Nou a year after his controversial move, the Portuguese winger was greeted with banners that read "Judas" and "traitor."

He was also showered with objects from the crowd including glass bottles, coins, and most famously, a pig's head.

It's not uncommon for players to switch between Borussia Dortmund and Bayern Munich.

But it was Mario Gotze's decision to announce his move on the eve of Dortmund's Champions League semi-final against Real Madrid in 2013 that made his move particularly contentious.

Gotze came under heavy fire from the club's fans for the reveal, with Dortmund subsequently requesting police presence at its training sessions in the days that followed for fear of reprisals, according to The Guardian.

"It could have been timed better," Dortmund boss at the time Jurgen Klopp said after. "Now I can say that time heals everything. It's going to take a while."

After Arsenal announced in summer 2012 that they'd agreed to sell Dutch striker Robin van Persie to rivals Manchester United, YouTube was alight with videos of Gunners fans burning their RVP jerseys.

"Judas scum" one such video was titled, while another was captioned "F--- off Van Persie! You're dead in our eyes!"

Van Persie tried to win back the fans when he retired by wearing a shirt that was half-Arsenal and half-United, however the stunt only attracted more abuse, with his former admirers labeling him a "slithering snake."

While he may have swapped from the red side of Manchester to the blue in 2009, Carlos Tevez isn't hated by United fans as you might expect.

The Argentine's move to Manchester City was somewhat forced upon him by United manager at the time Sir Alex Ferguson, who (until it was too late, anyway) refused to extend Tevez's contract at Old Trafford.

According to Bleacher Report, Tevez had young children at the time, and didn't want to uproot them from the area.

One historic season at Barcelona in 1996, in which Ronaldo scored 47 goals in 49 games, saw Inter Milan pay $22 million for his services, where he again shone, scoring 34 times in his debut season.

Injuries however meant the Brazilian would barely feature for the Italian club again, before he moved to Real Madrid in 2002.

After four years as Madrid's top scorer, he then went back to Italy, this time with AC Milan.

Never one to shy away from controversy, Zlatan Ibrahimovic has played for all three of Italy's biggest teams – Juventus, Inter Milan, and AC Milan.

It was the Swede's switch between the former two, however, that caused the most uproar.

Ibrahimovic helped guide Juve to consecutive Serie A titles in 2005 and 2006. However the club was found to be involved in a match fixing scandal, and it was relegated to Serie B.

Many of the club's biggest stars such as Alessandro Del Piero, David Trezeguet, and Pavel Nedved, pledged to stay, however Ibrahimovic demanded to leave, threatening legal action before joining Inter.

Given the derby between Greek sides Panathinaikos and Olympiakos is called the "Derby of the eternal enemies" – it's fair to say moving directly from one club to another wouldn't be wise.

Striker Mihalis Konstantinou clearly thought otherwise in 2005, however, when he swapped the green side of Athens for the red on a free transfer.

The switch was made even more controversial by the fact Konstantinou had chosen not to renew his contract with Panathinaikos due to his desire to move to one of Europe's bigger leagues.

A Cypriot Sol Campbell.

Emre can also count himself as one of Turkish football's biggest ever traitors.

Not only did the Turkish midfielder join rivals Fenerbahce in 2008, seven seasons after leaving boyhood club Galatasaray, he then went on to declare he had been a Fener fan his whole life, and that he kept posters of the club's greatest players on the walls of his house. Boo!

Clark, a boyhood Newcastle United fan, might have left St James' Park for rivals Sunderland in 1997, but he never really crossed the divide at heart.

Less than two years into his spell at the Stadium of Light, Clark was spotted at the 1999 FA Cup final supporting Newcastle and wearing a t-shirt saying "Sad Mackem Bastards."

"Mackem" is an informal nickname for people from Sunderland.

He never played for Sunderland again, and later went on to say signing for the club was a "mistake," according to the Evening Chronicle.

Most will remember Niko Kranjcar for being one of Harry Redknapp's favorite ever players, but before spells under the Englishman with Portsmouth, Tottenham, and QPR, Kranjcar was the golden boy of Croatian football.

Kranjcar spent most of his youth career with Dinamo Zagreb, and later became the club's youngest ever captain, aged just 17.

However, after an disagreement over wages midway through the 2004/05 season, he completed a surprise $2.1 million move to rivals Hajduk Split.

Later recalling the first time he met Zagreb as a Split player, Kranjcar told The Glasgow Times: "I had a couple of flares thrown at me. I couldn't hear my own thoughts when I had the ball.

"The flares missed me by inches."

Barmby angered Everton fans when he turned down the most lucrative contract offer in the club's history in order to force through a $7.5 million to Liverpool in July 2000.

And to really rub salt in the wounds, when the two sides met five months later, the Englishman scored the first goal of the game just 12 minutes in, then proceeded to celebrate wildly in front of the Anfield crowd.

Liverpool won the match 3-1, and Barmby has been a figure of hate for Evertonians ever since.

Days before Ashley Cole left Arsenal in 2006 he said, according to Bleacher Report: "I love this club but I suspect there are people at this club who do not want me to pull on a Gunners shirt again.

"I still won't sign for another Premiership team as I could not see myself playing against Arsenal. I would only want to play abroad."

He then, of course, joined Chelsea, where his wage more than doubled, earning him the nickname "Cashley" with Arsenal fans.

Over 100 players have played for both Boca Juniors and River Plate, but none have caused a stir quite like Oscar Ruggeri.

A Boca youth product, Ruggeri had made over 150 appearances for the club when in 1984, with Boca on the verge of bankruptcy, the Argentine defender committed nothing short of treason by jumping ship to rivals River.

The Boca fans' reaction was unthinkable.

"When I went from Boca to River, they set fire to my house with my parents inside," Ruggeri told MARCA.

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