Munna is a pink, nearly spherical, quadrupedal Pokémon of indefinable basis. It has four tiny tapered limbs and a tapered snout that largely obscures its sizable mouth. Munna has shiny, oval, red eyes with two discernible upper eyelashes. Between its eyes is an oval spot in a darker shade of pink, from which Munna can expel Dream Mist. Purple, five-petal flower markings with dark pink centers ornament much of its body. It is able to constantly float in the air.
Munna is able to eat the dreams of people and Pokémon, as well as project these dreams by expelling Dream Mist. A person whose dream was eaten by a Munna will forget the dream's contents. The Dream Mist will be pink if the dream was pleasant. However, Munna can also seek out and cure people and Pokémon who are having nightmares. Munna and its evolution are thought to share common ancestry with the Drowzee line according to one of Drowzee's Pokédex entries.
A Munna nicknamed Musha was the second Pokémon Black obtained. Musha was able to eat Black's dreams, clearing his mind of distractions, allowing him to perceive things a normal human can't. He first appeared in Choices.
In Generations I, III, and VII on Route 10, Picnicker Carol mentions that she wishes that there were pink Pokémon with floral patterns, a description of which Munna fits.
An employee of the Devon Corporation says that he wants to create a machine that can visually reproduce the dreams of Pokémon. Dream Mist, which Munna produces, can achieve this.
Munna is featured in the first promotional C-Gear skin. It is available by default in Japan but requires a password internationally.
Munna and Musharna were designed by Atsuko Nishida before the concept of the Dream World. When it was later added, it was associated with Munna and Musharna due to how easily they paired together.
Munna appears to be based on traditional Japanese incense burners called koro. These are used in traditional tea ceremonies, but many styles of koro have been developed to be used with insect repellent incense. These insect repellent koro are popularly shaped like a pig and can have patterns painted on them, such as floral patterns. Munna, like Drowzee, also seems to share some inspiration from the myth of the baku, tapir-like creatures that eat dreams.
Munna may be a combination of 夢 mu [on'yomi] (dream) and luna (Latin for moon) or 花 hana (flower). It may also involve ムシャムシャ mushamusha (onomatopoeia for eating, as it eats dreams), in line with the name of its evolved form, Musharna. Other possible references include Mana, which is mainly a concept for supernatural powers in many Pacific Islander cultures, and the Finnish muna (egg), as the Pokémon is egg-shaped. Its localized pronunciation, as featured in English media, suggests moon as a word of origin, and could thus be a combination of moon and one of the other examples ending with -na.
There is also a concept in Aikido called "Munen" or "Mushin" that roughly translates to "no-thought", where the conscious mind becomes instinctual and without being preoccupied by other thoughts. Instinct is a large part of what dreams are like, and given the names of its evolved form, Musharna, its name could be inspired by the name.