Sherlock Sammy (known as Encyclopedia Brown in the online version) is an imaginary character who appears in the book Sherlock Sammy Does it Again. He is a child detective who figures out mistakes in crimes and reveals them, making the criminal look like an idiot. He only appears because Greg says he is using Sammy's book for a book report. He even said he used the same exact book for reports five years straight.
- In Rodrick Rules, Sherlock Sammy has a striped shirt, but in the online book (displayed below), he has a black shirt.
- He is probably named after Sherlock Holmes because both of them solve mysteries.
- The online name Encyclopedia Brown is a real book.