In the midst of all that murder and mayhem in Black Mirror's "Demon 79" lies one hell of a disco banger.

Written by Bisha K. Ali and Charlie Brooker, the fifth episode of Season 6 makes not only a reference to, but makes a main character of disco legends Boney M. and their '70s Euro-disco mega single "Rasputin".

When footwear sales clerk Nida (We Are Lady Parts' Anjana Vasan) is taking much-needed time at home amid the unbridled racism of late '70s England, with the rise of Margaret Thatcher and the far-right fascist National Front. Inhaling her dinner, Nida ditches the violence and hate on the news for a Top of the Pops-style show, gazing adoringly at her TV as four Black disco icons — Boney M.'s Bobby Farrell, Liz Mitchell, Marcia Barrett, and Maizie Williams — sing and dance away on screen, sparkling in a world away from her own day.

SEE ALSO: 'Demon 79' explained: How Season 6's final episode fits into 'Black Mirror'

And it's this three minute song that accompanies a major change in Nida's life (and the world's) forever.

What is the song in "Demon 79"?

As the presenter says through Nida's TV set, disco group Boney M. is enjoying a number four spot on the chart with their 1978 single "Rasputin" from their third and biggest selling album Nightflight to Venus (it would actually hit number two on the UK chart). The infectious disco track chronicles long debated and analysed 20th century historical figure Grigori Rasputin, advisor of Tsar Nicholas II of Russia.

Rasputin's life and death have been pored over, debunked, fictionalised, and twisted by writers, authors, and yes, one disco foursome who really upped the focus on the man as "Russia's greatest love machine". Known as the "Mad Monk" for his self-proclamation as a holy man with healing powers, (as Boney M. sings, "He could preach the Bible like a preacher/Full of ecstasy and fire") Rasputin held influence over the Russian royal family, particularly the Tsarina, Alexandra, of the reigning Romanov family ("For the Queen, he was no wheeler-dealer/Though she'd heard the things he'd done/She believed he was a holy healer/Who would heal her son"). Rasputin was murdered on on Dec. 29, 1916 in a plot led by the super rich Prince Felix Yussupov — by poison, beating, being shot, then drowning ("They put some poison into his wine…He drank it all and said, ‘I feel fine.'")

Boney M.'s surreal take on Rasputin was written by producer Frank Farian, and became a global hit — including in Britain, where Nida is watching it in the Black Mirror episode.

Who does the demon appear as?

After Nida finds a wooden talisman in the Possetts department store basement, takes it home, and anoints it with her blood, the junior demon Gaap appears in her apartment to send her on her murderous quest — three human sacrifices over the next three days or the apocalypse happens.

Anjana Vasan summoning the power of disco in "Demon 79". Credit: Nick Wall / Netflix

Nida appears understandably terrified at Gaap's true demon form, so they decide to appear as something more familiar to her. "Yeah, sorry my regular appearance is probably a bit too much for this realm," Gaap says. Reading Nida's mind, the demon takes on the form of Bobby Farrell, Boney M's energetic disco king, played by Paapa Essiedu in a truly superb deadpan comedy style. "This any better for ya?" Gaap says. "I peered into your soul and apparently this is a physical look you find appealing, so...Maybe you saw this recently and liked it?"

Only Nida can see Gaap/Bobby Farrell. Credit: Nick Wall / Netflix

Wearing shimmering silver platform boots, white bell bottoms, aviator sunglasses, a white silk shirt and sequinned waistcoast, giant fluffy shoulder pads, and a sparkling tie, on inspection, Gaap isn't quite clear who this likeness is — "Am I, like, a clown? This how clowns dress in your realm?" But Gaap's choice of appealing physical likeness actually works, with Nida eventually coming around to her demonic companion.

Bobby Farrell at London's Odeon Hammersmith in 1978. Credit: Andre Csillag/Shutterstock

But whether or not Gaap is actually real or not, is another thing. "He is her sexual fantasy and her sinister fantasy," Mashable's Kristy Puchko writes. "Before Gaap shows up, Nida is already thirsting for blood...Maybe Nida, who's been desperately isolated since the death of her mother, is so overcome with rage and loneliness that she creates an imaginary friend to give her companionship, purpose, and an excuse to lash out at the ruthless world around her. Gaap's appearance lends credence to this idea."

Wait, is there another Boney M. song in "Demon 79"?

There is! Near the end of the episode, Boney M.'s earlier 1977 track "Ma Baker" from their second album Love for Sale plays as Nida takes control of her own narrative. After standing up to her racist co-worker Vicky (Katherine Rose Morley), Nida is on her way to murder white supremacist politician Michael Smart (David Shields), all set in slow-mo to the song written about legendary 1930s American outlaw Ma Barker. It's very fitting.

Where have I heard the song "Rasputin" before?

Beyond the dance floor? In two words: Just Dance.

"Rasputin" went viral in the late 2000s thanks to the game Just Dance 2. Released in 2010 with an energetic routine paired with Boney M.'s track, the game saw countless YouTubers recreating the choreography. It's appeared on Just Dance editions since then, and is still a community favourite.

A decade after its Just Dance debut, around 2020, "Rasputin" saw a resurgence on TikTok. The song has long made the rounds on the video sharing app, with users replicating Just Dance choreography in their own style — #rasputindancechallenge and #rasputindance have clocked up almost 162 million views to date, with Boney M.'s track scoring 2.8 million videos. The videos were particularly popular amid pandemic lockdowns and social distancing measures in 2020 and 2021.

With this resurgence in interest, UK artist Majestic released a remix of the track in 2021, which has seen 490 million streams on Spotify and 45 million streams on YouTube to date.

So, there you have it. 45 years after its release, Boney M.'s "Rasputin" is more popular than ever, moving through social media and TV shows like Black Mirror with all the finesse of the group's own energetic performances. Good luck getting it out of your head now.

How to watch: Black Mirror Season 6 is now on Netflix.