The Rowdyruff Boys are the male counterparts of the Powerpuff Girls created by Dr. Utobeans using a mixture of "snips and snails and a puppy dog tail" in the laboratory in the episode called The Rowdyruff Boys. His replacement for chemical X was in fact toilet water, as Mojo Jojo believed that would have the same potency as chemical X. An important difference between the trios is that the Powerpuff Girls got their names from Professor Utonium and the name of their team from the narrator, while the Rowdyruff Boys named themselves and their team. The boys' personalities also became more apparent after their resurrection.
The Rowdyruff Boys are violent bullies, have exactly the same powers as the Powerpuff Girls and in their first appearance nearly destroy them in a violent clash that reduced a great deal of Townsville to rubble (this is the first and one of the few times the Girls were defeated outright). The Girls were so ashamed of their defeat they planned to leave Townsville. Ms. Bellum suggested using a different tactic and told the girls that instead of fighting the boys, they should be nice to them. The boys were ultimately destroyed when the girls kissed them.
The Rowdyruff Boys were later resurrected by Him in the episode "The Boys Are Back in Town" and much to the Girls' shock, they were given immunity to the Girls' kisses, which made the Boys grow bigger and more powerful. The Boys eventually get their revenge on the Girls firstly by grossing them out in various ways, such as cracking their knuckles, picking scabs and spitting. The Boys then move on to play violent sports using the Girls as targets such as crushing them together to form a hockey puck, and then inflict a final victorious attack on them which once again almost destroys them. But after Buttercup recovers and made Butch bite his tongue he almost cried with pain and shrinks under his brothers' laughter. Blossom realized that when their masculinity was threatened they would shrink. The Girls do various things such as using makeup and babying them to shrink the Boys smaller than the buckles of their shoes and makes them cry with embarassment before Him restores the Boys to their original height, realizing defeat.
After their resurrection, the Boys sported more spiky hairstyles though they share similar hairstyles to the Girls'. Their signature colors are also darker than theirs. The Boys wear long-sleeved shirts with a black stripe in each, black trousers and black, low-top converse with white laces and white soles.
They are last seen as villains in "Custody Battle" where Mojo Jojo (their original creator prior to their first deaths) and Him (the one responsible for reviving them) are fighting over who is the more evil father. They both do various crimes to try to prove who is the more evil parent, in some cases the Boys are impressed by the various crimes, but eventually the Boys become annoyed with Mojo and Him's constant arguing and announce that they don't care who is more evil. Their final appearance at the end of the episode is when they fly off to destroy the Powerpuff Girls, the only evil thing they ever cared about (which subsequently brings Mojo Jojo and Him to happy tears at having done well as parents). They did not appear in The 10th Anniversary Special "The Powerpuff Girls Rule!!!"
As revealed in the "City of Clipsville", the Boys make an "appearance" in the memories of the Girls, who remember traveling to the future, becoming teenagers and meeting the teenage Rowdyruff Boys. Instead of a violent confrontation, the girls show a romantic interest in the boys, and each engage in innocent flirting with their counterparts. They have never defeated by The Powerpuff Girls in direct combat.