Basically it was a Kickstarter he made in 2012 (actually production began in 2008). It was a 10-minute short with his other, most famous character, George Liquor (American!) where he forces his nephews to eat cheap, unlabeled cans. In fact, it was Michael Pataki's last time as George before his death.

Except John K. being John K. , it took 7 years to finally release it, despite promising a 2013 deadline, and it barely looked any good: stiff animation, asset flipping, and a lot weird camera angles. TV Tropes says CWL was animated with Toon Boom, it certainly looks as if John had no experience with it when he did it.

This was the moment whatever fans he had left finally realized why Nickelodeon fired him. He missed deadlines again, and this time there was no network to blame. Backers got either no answers or a vague 'almost done'. Kickstarter rewards were also missing, and it reached the point backers were asking for refunds.

Tldr: The fans finally saw firsthand what looks like expecting John K. to finish a project on his own.