This Pokémon spent between 48 and 54 rounds as Munna.
Musha (Japanese: ムシャMusha) is a Musharna that Black owns in Pokémon Adventures and his second overall. Musha is consistently used to help clear Black's crowded thoughts, allowing him to sense hidden things at a superhuman level. As of The Power of Dreams, he is level 59 and his Characteristic is "takes plenty of siestas."
Musha eating Black's dreams
Black first met Musha when he was only five years old. During a battle with a wild Rufflet, Black's dreams caused him to begin daydreaming and made him completely unable to focus. This attracted Munna, who then bit down on Black's head, much to the horror of Cheren. This allowed Black to figure out that the Rufflet was angry because Bianca had stepped on its food, which led to him attacking her.
The next day, Black attempted to capture the Rufflet and make him his own Pokémon. Although it seemed like Black was at a disadvantage because he did not have another Pokémon to battle with, Black reveals that he asked Munna to help him with the reward of letting him eat his dreams. Together, Black and Munna battle the Rufflet and eventually defeat and capture him, where he was named Brav. Afterward, Black allows Munna to join his team and gives him the nickname Musha for his evolved form, Musharna.
As a Munna
Musha was first seen in Choices with Black and Brav. When Black went to rescue a runaway Tepig, he used Musha to scout out a wild attacking Sewaddle, allowing him to defeat it. Musha, along with Brav and Tep, were used against Hiker Andy, where they managed to defeat his three Pokémon in a Triple Battle. Musha was used to help Black find out a way to stop the fire that Andy's Cottonee had accidentally started.
In Letting Go, N begins to attack Black for not being able to hear the voice of his Pokémon. N has his Purrloin attack Musha with Night Slash, dealing major damage. Black soon realizes that all the "listen to your Pokémon" talk was about battling, and orders Musha to use Hidden Power to knock Purrloin back.
In Listening to Pokémon, Musha flies away from Black after sensing a powerful dream. With the help of Professor Fennel, Black and White find Musha in the hands of some Team Plasma Grunts. When Black tries to figure out a plan to defeat them, his brain overloads from trying to think of something that does not involve the Pokémon League. Musha becomes attracted to this overflow of dreams and flies from the grasp of the Grunts and goes back to Black. With the help of Musha, Black manages to defeat the Grunts and drive them out.
In Underground Showdown, Musha is used in Black's Gym battle against the Gym Leader of Driftveil City, Clay. Musha battles Clay's Palpitoad and is trapped by its long tongue. Eventually Musha managed to knock out Palpitoad with a Zen Headbutt but faints in the process.
In A Wretched Reunion, after N defeats Alder, Black attempts to have Musha eat his dreams again, but owing to several setbacks at the hands of Team Plasma, Black's dreams have already begun to surface as nightmares. Musha refuses Black's command and floats away, seemingly abandoning him. N claims that Musha only followed Black's orders because he considers Black's dreams of winning the Pokémon League to be tasty and kept him fed; after the taste of Black's dreams changed, their relationship was broken. This news devastates Black to the point of putting him into a brief coma.
Musha eventually returns to Black in True Friends, now evolved into a Musharna, where his Dream Mist was instrumental in helping Black defeat Cheren. It is later revealed in a flashback that Musha left Black not because of his dreams, but because Munna wanted to become stronger and needed a "power source" to do so. Caitlin, who saw Musha wandering around the Pokémon League, used a Moon Stone on him to evolve. Against Ghetsis, Musha defeats his Seismitoad and by eating Black's dreams, helps Black and Costa defeat his Volcarona.
Personality and characteristics
Musha, at times, is shown to be very gluttonous for his favorite food, dreams, even flying away from his Trainer when he senses a tasty one in the vicinity. He is a very happy-go-lucky Pokémon, and is often seen enjoying whatever he is doing. Musha has a very close bond with Black, with Black enter a brief coma when believing Musha only cared about him for his dreams. Despite having a close bond with Black Musha often acts on his own without consulting Black, which often leads to miscommunication between the two.