Babymetal: Mixing cute with crushing riffs and conquering the West
One might expect heavy metal songs to include words like "death", "skull", "pain" but certainly not "gimme chocolate".
But for Japanese group Babymetal, "expected" is not part of the agenda.
Their latest track, Gimme Chocolate, is best described as where cute meets crushing riffs - and they are taking the West by storm.
Formed in 2010, the trio of Su-metal, 16, Yuimetal and Moametal, both 15, is the face of the "Metal Resistance".
And the resistance of even hardcore metalheads seems futile, with the girls' eponymous debut album making it to No 1 on the iTunes metal charts in the US, UK and Canada.
It has been a extraordinary year for the group since they held their first solo overseas concert here in December last year.
In the past month, they have been on tour in Europe, before crossing the pond to join Lady Gaga on her US-wide artRAVE: The ARTPOP Ball tour.
Tonight in Denver, Colorado, they will open Lady Gaga's show for the fifth and last time.
Their Stateside sweep comes hot on the heels of their UK debut at the Sonisphere Festival last month, where they rubbed shoulders with metal legends Iron Maiden, Anthrax, Slayer and Megadeth.
Perhaps a question to ask would be why Babymetal succeeded in the West while other J-pop acts often fail to make an impression?
SOCIAL MEDIA EFFECT
Part of the Western media has taken the "Weird Japan" angle to explain why the fusion of idol cuteness and hard metal works. Others acknowledge the role played by social media.
Gimme Chocolate has had 12.8 million YouTube views since its release in late February.
USA Today ran an online story headlined: "Babymetal's video is the greatest ever - or the worst".
Alexander Milas, editor-in-chief of Metal Hammer magazine, told BBC News that the group's success is "a terrific barometer of how important social media is these days".
He added: "Babymetal has descended on us from a lot of non-traditional means. It's not because Metal Hammer said 'check this out'... people have discovered this on their own and they have ownership. It has suddenly become a juggernaut."
In a Los Angeles Times report last week, they were called "just about the only metal group sticking with the mission of the genre - freaking people out and putting on a hell of a spectacle".
There has been criticism though, with some calling them manufactured.
The girls have readily admitted they had never heard of metal music before joining the group, and were formed as a affiliate of the J-pop group Sakura Gakuin.
Babymetal is a play on the Japanese pronunciation of "heavy metal", while "baby" also signifies a newborn form of the music.
Or if you would have it, according to their producer - known only as Kobametal - the group's name came to him as a "divine message".
They have also been given a mythic origin story, told in a Star Wars-style intro video played before their concerts.
It says that in a world ruled by a legion of idols, all non-idol music was considered harmful.
Hearing the cries of oppressed metal fans, the Fox God (Kitsune-sama) selected the trio to lead a Metal Resistance and "make the world become one with heavy metal again".
Heavy talk aside, the group's songs tend to be more lighthearted, featuring themes such as craving for chocolate while worrying about their weight (Gimme Chocolate); and tricking their dads into giving them what they want (Onedari Daisakusen).
But there are serious tunes too, like their anti-bullying anthem Ijime, Dame, Zettai (Bullying, No, Absolutely).
So what's next after their world tour?
Fears that the group may disband have lingered for some time, as the girls are supposed to "graduate" from parent idol group Sakura Gakuen after junior high school.
But that date has come and gone and the girls are still rocking, dancing and screaming.