John Oliver made TV history this week by buying and then forgiving $15 million (£10.3 million) in medical debt.
The comedian's stunt which helped 9,000 people has been widely praised and shone a light on an entire US industry dedicated to chasing down some of the $12 trillion dollars owed by American households.
Oliver said: "Debt-buying is a grimy business and badly needs more oversight, because as it stands any idiot can get into it. And I can prove that to you because I am an idiot and we started a debt-buying company."
For just $50 Oliver set up a company called Central Asset Recovery Professionals (CARP, also a bottom-feeding fish) and bought the entire debt for $60,000 along with names, addresses and social security numbers.
He added: "We bought it, which is absolutely terrifying because it means if I wanted to, I could legally have Carp take possession of that list and have employees start calling people, turning their lives upside down over medical debt."
But what did he actually do? How can you just buy and forgive debt and why do people in the US have medical debt in the first place?
Well, if you've asked one of these questions then you're not alone.
A handy Reddit thread asking just that has sought to explain the stunt for those with a less than comprehensive understanding of economics and the US medical system...
And here's how someone can rack up the debt in the first place...
TL:DR John Oliver is a legend and did a very good thing.