Sulu was a hamster that is adopted by George Beard and Harold Hutchins.
He used to be Melvin Sneedly's pet. He was also known as Sulu the bionic hamster. Melvin Sneedly combined Sulu with a bionic robot, transforming Sulu into a cybotic hamster using the Combine-o-Tron 2000.
Sulu is a brown, fuzzy hamster. Beyond his furry exterior is a mechanical exo-skeleton, the source of Sulu's bionic powers.
Sulu has a lot of heart and is good friends with George and Harold. But his feelings are easily hurt, such, as the time when Sulu spanks Melvin.
The Big, Bad Battle of the Bionic Booger Boy
In Books 6 and 7, Sulu is Melvin Sneedly's hamster. Melvin used Sulu as his project, transforming him into a cyborg. With his newfound powers, Sulu spanked Melvin. Melvin was so upset that he abandoned Sulu. As everyone left the classroom, George and Harold adopted Sulu. Later, as Captain Underpants failed to defeat the Bionic Booger Boy, Sulu came and defeated the Booger Boy, and later rescued his former owner and George and Harold from Carl, Trixie, and Frankenbooger, who had been formed from the split parts of the Bionic Booger Boy. Sulu went back in time in Part 2 with George and Harold.
The Preposterous Plight of the Purple Potty People
Sulu turns into a giant, evil hamster when George and Harold's evil twins capture Cracker and Sulu. Then they hypnotize them into putting them under their command. But Crackers does not get hypnotized because she is a girl. But Sulu gets turned into a giant when evil George and Harold use the Goosy Grow 4000 and goes on a rampage.Then George and Harold find Captain Underpants near Mr. Krupp's house and he defeats Sulu. But later Sulu gets de-hypnotized and shrunk back to his normal size with the Shrinky-Pig 2000 by George and Harold. And he gets turned back to a good hamster.
The Revolting Revenge of the Radioactive Robo-Boxers and fate
In this epic novel, Sulu was transported along with Crackers and Tippy Tinkletrousers approximately 13.77 billion years backward in time, where there was no matter yet. Unfortunately, he had gone back in time just when Tippy's thermonuclear bomb was merely seconds from detonation. The bomb then exploded with a "ka-bloosh", presumably killing Sulu, Crackers, as well as Tippy. At the end of Sir Stinks-A-Lot, George and Harold decide to use the Robo-Squid suit in an attempt to rescue him from this fate.
- Dav Pilkey's official website offers an explanation for Sulu's changing sizes, which is related to the Flexo-Growmonic Steel that Sulu's cyborg body is made out of. 
- Sulu is named after Sulu the iguana in the Mr. Show episode "The Biggest Failure in Broadway History". This is also the origin of the "BAD SULU" paddle.
- He is the father of Orlando, Dawn, and Tony (Crackers's children).
- It is unknown how Sulu was able to mate with Crackers despite not being of the same species, however, Harold speculates that it is because his genes were mutated during his fusion with the Robotic Endoskeleton.