A who's who scam is when someone pretends to be from a famous organization or famous person and asks you for money in return for something special. For example, they might say that if you send them money, they will give you a expensive prize. However, once you send them the money, they disappear and you don't get your prize. The scammers usually tell you a lot of lies and try to be believable and convincing, but it's always false and the scammers are trying to get your money.