Companies that make money by buying other people's overdue debts might seem like scumbags. And they are, according to John Oliver, whose latest episode of "Last Week Tonight" explored their seedy business practices.

To show how bad the industry is, Oliver pulled a sample of recorded messages left on people's phones from collectors who bullied debtors by belittling their manhood or even telling them they should commit suicide. Another actually threatened to kidnap, kill and eat a debtor's dog.

Oliver concedes that those cases are extreme examples of a corrupt system. More common incidents of abuse involve "zombie debts" - outstanding balances that have exceeded the statute of limitations for collection, have been dispatched through bankruptcy or have been repaid.

"The comparison [to zombies] is actually quite apt," Oliver quips. "Because just like on The Walking Dead, zombie debt comes back from the grave, is incredibly hard to deal with and seems to disproportionately impact minorities."

Debt collection industry operates with little oversight

So how are debt companies able to do operate in this unethical and - in some cases - illegal manner? Because the industry operates with little oversight, and it is ludicrously easy for just about anyone to become a debt buyer or collector.

"There are places in this country where you need to fill out less paperwork to start collecting money from people's pockets than you do to collect fish from a fucking lake," Oliver says.

To prove his point, Oliver set up his own debt buying agency called Central Asset Recovery Professionals - or CARP, in honor of the bottom feeding fish. His corporation legally bought up just under $15-million dollars worth of consumer debt stemming from unpaid medical bills. But instead of exploiting the misery of others, he used his powers of procurement to outdo Oprah's biggest TV giveaway. (Yes, we mean the infamous "you get a car" episode).

Check out the clip for the happy ending to Oliver's gut-wrenching exposé.