The Beagle Boys make their debut in Kingdom Hearts 3D: Dream Drop Distance. They appear in the Country of the Musketeers world, where they serve as the henchmen of Captain Pete, the corrupt leader of the musketeers. These Beagle Boys originate from the direct-to-video Disney film, Mickey, Donald, Goofy: The Three Musketeers.
They appear in Country of the Musketeers, serving under Pete. They first appear after the Tyrnato Rex is defeated, knocking Sora off of Minnie's carriage. They take Minnie to a tower, as part of Pete's plan to takeover the kingdom; however, they are tracked down by Sora and the Musketeers. Though Goofy's quick thinking, they are knocked out of the window and down into the river below. They later assist Pete in fighting Sora, serving as shields until Pete has lost his patience with their incompetence.
In Riku's side, they practice the trap set for the musketeers beforehand. Riku follows them and frees Minnie as the small Beagle returns for the crank that activates the trap. He chases them down and knocks them out, taking the crank and preventing the trap from working.
The Beagle Boys differ only in size and attitude, since their attire is the same, that of black uniforms with dark brown hooded cloaks. They each sport a rapier used in 17th century France.
Together, they are loyal to their boss, Pete, but bumble almost everything they are tasked with. Although they are clever enough to come up with traps, they still manage to mess up.
The Beagle Boys were created in 1951 by Carl Barks as recurring villains for Scrooge McDuck in the character's comic book stories. They are a clan of criminals who frequently attempt to rob Scrooge's Money Bin, a task they fail at more often than not. In the comics they usually bore no specific names, and did not have any specific physical differences other than their arrest card placards. Though they usually work alone (only with fellow Beagles), they have been known to team-up with other criminals like Magica de Spell, Pete, or Mad Madam Mim, or hire out their services to such as Flintheart Glomgold. The Beagle Boys later appeared as regular antagonists on the animated series DuckTales, where they were given individual designs and personalities.
In Mickey, Donald, and Goofy: The Three Musketeers, these particular Beagle Boys are first seen at Princess Minnie's palace, trying to drop a safe onto her. Their attempt fails, and they run off to tell their boss, revealed to be Pete, captain of the Royal Musketeers. Pete is outraged at the Beagle Boys, as the plan was not to kill the princess, but to capture her so that he can become king. As punishment, they are dropped into a shallow "pit", and later they are again sent to kidnap Minnie. They waylay her coach and lock her in a tower, but they are thwarted by new Musketeers Mickey, Donald, and Goofy. When Pete changes his plans to kidnapping her at the opera, the Beagle Boys catch Donald and bring him to Pete. At the opera, Pete and two of the Beagle Boys capture Minnie and lock her in a trunk, while the shortest one impersonates her and declares Pete king. Mickey, Donald and Goofy confront the Beagle Boys backstage, and during the battle, they are dropped through the stage. They are not seen again for the rest of the movie.