At his out-of-the-way house in the forested German hills, Joerg Sprave spends his time building mutant crossbows and powerful slingshots -- and hounding one of the world's biggest technology companies.
The 54-year-old has for years uploaded clips of his ever-wackier projectile-throwing creations to YouTube, where hundreds of millions of views and 2.4 million subscribers put him in the top 50 channels nationwide.
But years of hard blows to those making their living on the platform have turned him into a campaigner against YouTube itself, claiming to have enlisted some 26,000 fellow creators worldwide in a fight for better conditions and the unexpected backing one of Germany's biggest unions.
"I'm not fighting for myself, I'm fighting because I love YouTube, and I fear that the management's mistakes are endangering it," Sprave told AFP.
Sprave and the members of his "YouTubers' Union" Facebook group aren't global YouTube royalty, like gamer Felix Kjellberg with his 102 million followers under the alias PewDiePie.
But until 2017, many earned a healthy living from long days of creating, filming and building communities around their videos.
Sprave says he used to make around 6,000 euros ($6,500) per month after going full-time as a YouTuber.
These days he's lucky to break 1,200 euros.
His savings and his family income mean "I can put my channel at stake, firing massive broadsides at YouTube and Google" in the name of a battle for more rights, he says.
"For a lot of my colleagues it's very different, they'd kill themselves financially if they did that."
- 'We want to know the rules' -
YouTube earns money by selling advertising slots before or during videos uploaded by its millions of users, sharing some of the revenue with users whose popular channels have earned them the title of "Partner".
In 2012-17, "we were largely free when it came to content, and well paid if we managed to get enough views", Sprave recalls.
But advertisers keen to skirt controversy pressured YouTube to allow them more fine-grained control.
These days especially controversial videos, including some of Sprave's, are shut out from "monetisation" entirely, while all are placed into categories and awarded scores measuring their attractiveness to advertisers -- both invisible to creators.
"We insist on transparency. We want to know the rules by which we are being judged," Sprave fumes.
And he complains there's often no human interlocutor.
Powerful German union IG Metall, already closely following the growing "gig" or "platform" economy of people working for online portals, has joined his battle.
"We don't just want to stand and watch how the world of work develops, but to shape it ourselves from an early stage," says IG Metall official Robert Fuss.
- 'Very expensive' for YouTube -
Google declined to meet Sprave alongside union officials in October, saying he and his group aren't representative of YouTubers.
Hoping to step up the pressure, the campaigners launched a mass letter-writing campaign targeting the company's California headquarters -- so far to little effect.
But they have other arrows in their quiver that could become "very expensive" for YouTube, Fuss says.
One angle of attack is Europe's General Data Protection Regulation (GDPR), under which companies must provide users with access to their personal data on pain of massive fines.
That could cover the categories and advertiser scores handed out secretly by YouTube, Sprave and IG Metall believe.
Meanwhile a battle with wider implications could come over the question of "false self-employment".
IG Metall sees a potential legal case that YouTubers are so closely tied to the platform that they are de facto employees.
A court ruling that this applies to YouTubers would imply a massive financial blow of back payments for social security and pension contributions.
"There's a new class of workers who are called 'self-employed' entrepreneurs by the platforms, but don't deal with them like entrepreneurs on a level playing field," says IG Metall's Fuss.
"There's a growing awareness among politicians that people working on digital platforms need protection," he added, pointing to a recent California law classifying Uber drivers as employees.
- 'Edgy content' -
But ultimately "we don't want to be YouTube employees. We want to be treated like partners", Sprave says.
Google dismisses the prospect of a court case.
A spokesman told AFP that "contrary to what is being claimed, YouTube creators are not YouTube employees by legal status".
Nevertheless it is taking some pains to coax online creatives towards its vision of YouTube as one revenue stream for them among many.
In a November blog post, YouTube chief executive Susan Wojcicki pointed to growing numbers of creators earning five or six figures annually -- without providing absolute numbers -- and prodded readers towards alternative sources of income such as fan merchandise.
But she also trailed "experiments" to match appropriate advertisers with "content that could be considered edgy" and that has been flagged by automated systems for limited or no ad sales.
"Hundreds of thousands of dollars in ads" had already been sold against such videos in the scheme's first month, Wojcicki added.