You receive a letter, generically addressed, from a person in a foreign country. The writer claims to have been estranged from an improbably large sum of money. Though you are a stranger to him, he needs your help in getting it back. He promises to handsomely reward you in exchange for this minor favor. Please contact him to discuss the details.
Most of us only read this kind of thing if we dip into our email spam folder. Everyone knows that Nigerian Prince doesn’t really need your help, and isn’t really a Nigerian Prince. If you respond, the email writer’s plan is to tell you that he only needs a small (compared to the payment he’s promised) loan to reunite him with his money. If you give him any money, it’s only a matter of time before he claims to have run into a logistical issue, and that he needs another loan to deal with it. He’ll string you along until satisfied that he’s bled you dry. Or, if you give him enough personal information and he’s savvy enough, he’ll just hack your bank account.
“Who still falls for this shit?” you might wonder when you look through your spam folder, “Their returns must be minimal. It’s the oldest trick in the book.”