Rappers have been trading insults since the dawn of hip-hop.
It's part of the culture - a test of lyrical skill and a declaration of superiority that has produced hundreds of classic "diss tracks", from 2Pac's Hit 'Em Up to Jay-Z's Takeover.
The latest beef has erupted between three of hip-hop's biggest stars - Drake, Kendrick Lamar and J Cole - and was triggered by a seemingly innocuous lyric praising their respective careers.
Here's a guide to what's happened so far.
Who are the main players?
Drake (above left) - the Canadian actor-turned-musician whose vulnerable blend of rap and R&B has made him the most commercially successful hip-hop artist of the 21st Century. Among his multi-platinum hits are tracks like Hotline Bling, One Dance and Hold On We're Going Home.
Kendrick Lamar (centre) - A Compton-born rapper whose compelling rhymes and conceptual vision have seen him named the best rapper of his generation. One of the most inventive lyricists in the game, he tackles big topics like police brutality, black self-worth and his own internal conflicts. In 2018, he became the first hip-hop artist to win the Pulitzer Prize for music.
J Cole (right) - Born in Germany and raised in North Carolina, J Cole was mentored by Jay-Z and went on to score hits with songs like Middle Child and Deja Vu. But he grew disenchanted with the trappings of commercial success and began to forge his own path with more introspective, analytical songs, resulting in some of the most popular and successful music of his career.
How did the beef start?
When Kendrick Lamar was a young up-and-comer, Drake offered him a helping hand by inviting him onto his Take Care album and giving him an opening spot on his 2012 Club Paradise Tour.
But in 2013, after the success of Lamar's debut album Good Kid, m.A.A.d City, he made his ambitions clear.
During a guest verse on Big Sean's Control, he called out Drake, J Cole, Meek Mill, Mac Miller, Pusha T and a host of other rappers, warning them: "I got love for you all, but I'm trying to murder you."
Asked about the diss, Drake told Billboard Magazine: "I didn't really have anything to say about it. It just sounded like an ambitious thought to me. That's all it was.
"I know good and well that [Lamar] 's not murdering me, at all, in any platform. So when that day presents itself, I guess we can revisit the topic."
The rappers traded a few jibes over the next few years (Lamar memorably boasted that he'd "tucked a sensitive rapper back in his pajama clothes" during the BET hip-hop awards) but it never seemed particularly serious.
What triggered the latest escalation?
The initial spark was a gesture towards unity, rather than division.
In October last year, Drake released his eighth album For All The Dogs, which featured a collaboration with J Cole called First Person Shooter.
In one verse, Cole suggested that he, Drake and Kendrick were the "big three" of the current era of hip-hop.
"Love when they argue the hardest MC / Is it K. Dot [Kendrick]? Is it Aubrey [Drake]? Or me? / We the big three, like we started a league."
The song debuted at the top of the US singles chart, becoming Drake's 13th and Cole's first number-one song.
The achievement meant Drake tied with Michael Jackson for the most number one singles by a male solo artist.
A week later, Taylor Swift's Cruel Summer replaced them at number one, and the moment seemed to have passed. But privately, Kendrick had taken note - and he wasn't happy.
What did Kendrick Lamar say?
In March 2024, producer Metro Boomin' and rapper Future released a collaborative album called We Don't Trust You.
Hidden in the tracklisting was a song called Like That with an uncredited verse by Kendrick Lamar... and it was explosive.
With a tightly-wound, expletive-laden delivery, he took aim at Cole's verse, claiming there was no "big three - it's just big me".
He went on to call Drake and Cole's best verses insubstantial - "a light pack" - and declared he was the Prince to Drake's Michael Jackson.
The power of the verse can't really be conveyed in print, but when it ends with Lamar promising to put all of Drake and J Cole's "dogs" in the "pet sematary" - the name of a Stephen King 1983 horror novel - you know a fuse has been lit.
(NB: Lamar doesn't mean literal pet dogs, but the rappers' nearest and dearest. The lyric doubles up as a reference to Drake's album title, For All The Dogs)
It's worth noting that the placement of Lamar's verse is also significant, as Metro Boomin' is a former Drake collaborator who fell out with the Canadian star.
Metro, whose real name is Leland Wayne, produced the majority of Drake's 2015 album What A Time To Be Alive, but a promised sequel never materialised, allegedly leading to bad blood between the pair.
In 2022, the producer removed Drake from a song called Trance, and unfollowed him on Instagram.
Did Drake accept defeat?
Of course not.
Drake appeared to address Kendrick's verse in a concert in Florida, with a pugnacious message to the crowd.
"A lot of people ask me how I'm feeling," he said. "I'ma let you know I'm feeling.
"I got my [expletive] head up high, my back straight, I'm 10 [expletive] toes down in Florida and anywhere else I go. And I know that no matter what, it's not a [person] on this What's Kendrick Lamar’s beef with Drake and J Cole?earth that could ever [expletive] with me in my life!"
Presumably that was the end of it?
Double of course not!
Two weeks later, J Cole offered his own reply to Kendrick's verse, in a track called 7 Minute Drill on his surprise album Might Delete Later.
"I got a phone call, they say that somebody dissing / You want some attention, it come with extensions," he rapped. "He still doing shows but fell off like The Simpsons."
He continued by critiquing Kendrick's discography, calling his debut a "classic", but his most recent effort - a sprawling double album called Mr Morale and the Big Steppers - "tragic".
"Your third [album] was massive and that was your prime," he continued, "I was trailing right behind and I just now hit mine."
He finished up by saying he still respected Lamar, but wouldn't hesitate to destroy him if the insults continued.
"Push come to shove on this mic I will humble him."
Did J Cole stand by his words?
Almost immediately after releasing 7 Minute Drill, Cole realised it had been a huge "misstep".
Speaking on stage at the Dreamville Festival in North Carolina, he apologised for the song, praised Lamar's back catalogue and asked for forgiveness.
"I ain't gonna lie to y'all the past two days felt terrible," he told an audience at the Dreamville Festival in North Carolina.
He explained that he'd caved into pressure to respond to Lamar's diss, but the result was the "lamest, goofiest" thing he'd ever recorded.
Vowing to scrub the song from streaming services, he added that he would "take it on the chin" if Lamar wanted to respond.
As the star rapped on his 2013 track Crunch Time, "Only thing worse than death is a regret-filled coffin".
Will Drake keep this going, long after everyone else has moved on?
Like a true rap arsonist, Drake tried to reignite the fire Cole had extinguished.
On April 13, Drake released a song called Push Ups (Drop and Give Me 50), in which he took aim at Lamar's height, calling him a midget (he's 5ft 4in tall) and a record label puppet who's forced to collaborate with pop artists.
"Maroon 5 need a verse, you better make it witty/Then we need a verse for the Swifties," he cajoled.
He also took issue with Lamar's position in the hip-hop hierarchy, suggesting other artists had overtaken him.
"Pipsqueak, pipe down, you ain't in no big three/SZA got you wiped down/Travis got you wiped down, Savage got you wiped down."
He also tagged Future, The Weeknd and Rick Ross in the song.
Has anyone else - like Drake's mum - responded?
Funny you should ask.
Within hours of Drake's diss, Rick Ross shot back in a track called Champagne Moments, alleging the star had undergone plastic surgery - including a nose job, fake abs and a Brazilian Butt Lift.
The accusation resulted in Drake's mum texting him to ask if the rumours were true.
He shared their exchange on Instagram, marking the point where this rap beef went past its sell-by-date.
But it didn't end there. Oh no.
On 21 April, Kanye West sided with Kendrick Lamar, releasing a remix of Like That where he took aim at Drake's major label record deal, suggesting he'd been short-changed.
And he dismissed Drake and Cole's lyrics, rapping: "Y'all so out of sight, out of mind/I can't even think of a Drake line".
Meanwhile, Drake tried to goad Lamar into responding, by dropping yet another diss track.
Called Taylor Made Freestyle, it suggested Lamar was too cowardly to release music in the same week as Taylor Swift's The Tortured Poets Department.
Adding insult to injury, Drake apparently used Artificial Intelligence to deliver two of the voices in the style of Lamar's heroes, Tupac Shakur and Snoop Dogg.
Following complaints from Shakur's estate, the song was removed from Drake's social media feeds.
What did Kendrick say in his diss track?
Kendrick finally responded with a full-blown, six-minute diss track at the end of April.
Titled Euphoria (a reference to the HBO show where Drake serves as an executive producer), it read like a laundry list of complaints against his sparring partner.
Lamar called Drake "predictable", a "master manipulator" and an "habitual liar". He also repeated Rick Ross's dig about Drake's fake abs, and called the star's parenting skills into question.
But mostly, he said he really, really didn't like Drake.
"Let me say I'm the biggest hater," he rapped. "I hate the way that you walk, the way that you talk, I hate the way that you dress."
Drake responded by posting a screenshot of the movie 10 Things I Hate About You, comparing Lamar's lyrics to the teenage poetry recited by one of the characters.
Less than 72 hours after dropping Euphoria, Lamar followed up with a second song, called 6:16 in LA.
In it, he claimed that someone inside Drake's organisation was leaking damaging information.
"You must be a terrible person/ Everyone inside your team is whispering that you deserve it."
Why did it suddenly get personal?
Lamar's accusation that Drake "don't know nothin'" about raising a son appears to have rankled.
On Saturday 4 May, Drake shot back with a song called Family Matters, which took the feud to new heights.
"You mentioned my seed, now deal with his dad," he declared. "I gotta go bad, I gotta go bad."
Among the song's most shocking allegations, Drake speculated that Lamar might be a perpetrator of domestic abuse (the star has never faced such an allegation).
Within 20 minutes, Lamar retaliated with a third diss track, Meet The Grahams, which opened with the ominous warning: "You [messed] up the minute you called out my family's name".
Each verse was addressed to one of Drake's closest family members - his mother, his father and his six-year-old son, Adonis. To each of them, he listed a litany of the rapper's supposed failures.
Among the claims, he said Drake had secretly fathered second child, and was addicted to gambling, sex and drugs.
Drake responded on Instagram by asking whoever had his "hidden daughter" to hand her back, adding that Lamar's claims were a "shambles"
How will it end?
The war of words shows no signs of subsiding. If anything, the frequency of the star's attacks is increasing.
The feud is good for business, however. Both Push Ups and Like That are safely nestled in the US and UK charts, with the latest diss tracks certain to follow.
However, there are signs that some listeners are growing tired of the constant back and forth.
"This whole feud has started to reveal itself to be an ouroboros of attention and social-media commentary more than any actual referendum on two rappers' abilities," wrote Rolling Stone magazine's senior music editor Jeff Ihaza in an opinion column on 2 May.
"It feels like such a colossal waste of energy."