Even the hardly shaken Powerpuff Girls, starting with Bubbles who preferred not to risk having cooties, were terrified of this boy because of the so-called illness, forcing them to fly away just before Harry could lay his lips on the Girls; leaving Harry by his lonesome and feeling the hurt of condemnation. Mojo Jojo had saw this happening and smiled wickedly, knowing he could use Harry to his advantage as in pulling gem heists and bank robberies without being stopped or be injured by fighting, so long as Mojo had Harry by his side. Promptly, Mojo went over to him on the sidewalk, sat next to the outcast and giving a simple hello. Harry also terrorized the Powerpuff Girls in their dream, even his face was the portrayal of the fake illness and Harry himself was the emblem of fear. They even woke up gasping with the Hotline ringing soon after.
The first time that Harry was being used to scare away the Powerpuff Girls was during the bank, when the girls were about to arrest Mojo for robbing the bank, he fake pleaded for mercy to not maul him with their superpowers claiming to have no defenses, unless they counted Harry who he unveiled, who scared the Girls away immediately with him being a dreadful reminder of cooties, just as Mojo had expected from the events he witnessed the day before, happy it wasn't just a fluke, declaring with Harry that he could take over the universe. Due to these circumstances, Mojo got away with the cash with no struggle and without being arrested. That night, the Girls realized they had no defenses against cooties other than escape and the next day, he pulled a jewel heist and the Girls knew that he had Harry at his disposal, especially after what happened at the bank. This forced Blossom to ask him to stop robbing the jewelry store nicely, which is something that does not usually happen, but Mojo falsified fear again and said his plans were foiled by the super-heroine trio and he was off to jail, wondering what to do. Like the bank robbery incident, he showed Harry again and like last time, they were scared away by the kid, allowing Mojo to get away with the smuggled gems without trouble.
Because of Harry's ability to end the fight before it even commences due to being the fear of the Girls, it allowed Mojo freedom to run amok in Townsville, being able to commit crimes such as stealing from banks, jewelry stores, robbing fine gold, stealing the belongings of innocent folks, petty thefts involving robbing from old ladies, all of this because the Girls would run away terrified at the sight of Harry. No matter the circumstances, time, place, or event, the reaction of the Girls seeing Harry Pitt was the same one: running away unable to lay a hand on Mojo.
When the two Mobsters who were about to steal money from a truck were about to be stopped by the Girls, Mojo came to that site much to their horror, and again used Harry Pitt, and the result was the same as always: they flew away terrified of the dirty child. This earned Mojo some brand new minions for being able to frighten the Girls, as no one else pulled that stunt off before. So as Mojo and his band went around committing robberies, growing in power by forming alliances due to being unstoppable, the Hotline would ring time and time again, but the Girls would fail to answer, knowing they were powerless against Harry Pitt and his cooties; otherwise they would have been able to defeat Mojo and his band. To make matters worse, the media had begun questioning the whereabouts of the trio, but knowing who they were up against, they even failed to answer the call of the media and especially refused to pick up the constantly ringing Hotline. Thanks to Harry Pitt's ability of terrorizing the Girls, Mojo even threatened to take over Townsville, due to its only defense being of no use, and become its new Mayor, but the bargain was simple: the Mayor could be a simple house boy who would tickle Mojo's fancy on demand while Mojo himself ruled Townsville and the world. As expected, the Mayor took the bargain.
Meanwhile, Townsville was losing its stability without their superheroes to fight crime. Finally, they had no choice but to answer the Hotline, although they seemed very unwilling to. The reason for that reluctance being the Girls knowing about a certain ape wielding a certain boy with a certain sickness, from whom and to which they would always run in terror, thus rendering them unable to stop the crime being committed.
The Mayor called, while being held hostage by the two mobsters, saying that he could not get his Pickle Jar open. What they did not realize is that it was a trap staged by Mojo, and immediately they fell into a pitfall trap. Mojo even left Harry alone with the Girls in the pit, the Girls' worst fear. So after seconds of chasing the Girls around in the pit, Blossom was finally cornered and Harry gave her a kiss. Despite thinking she was stuck with the cooties, nothing happened because the cooties, as the Girls noticed, were nonexistent and there was nothing to fear about the boy. In return, the Girls smooched Harry up and they gave Mojo the usual pounding and finally had him arrested and they left the boy in the pit, who was nothing more than dizzy with happiness, sitting on the ground with a happy smile on his face knowing that his affection for others was acknowledged. Also, Harry was left with lipstick marks all over his face.
Although he was used for evil intentions, Harry himself didn't appear to be at all evil, rather just a boy looking for someone to return affection to him and not be afraid. Also, Harry didn't appear to be terrorizing off the Girls intently; he didn't even have to try nor did he have to say anything at all, be it menacing or reasoning. One could say that Harry was a living kryptonite to the Girls before they realized cooties were not real if he could defeat them so easily with unintentionally scaring them.
- His name is a pun of the term "hairy pits".