Lopunny is a bipedal, rabbit-like Pokémon with a dark brown fur and a short, round tail. It has pink eyes with black markings on the inner edge, long tufts of cream-colored fur above its eyes, and a small, pink nose. Its long ears, which bend shortly above its head, end in fluffy, cream-colored fur. Lopunny is very proud of these ears and never fails to groom them. If the ears are roughly handled, Lopunny will kick in retaliation. Its head, body, and hips are covered in dark brown fur, while its wrists and lower legs are covered in fluffy, cream-colored fur similar to its ears.
As Mega Lopunny, its personality drastically changes, becoming extremely aggressive with wild fighting instincts. In order to become more capable of fighting, it sheds the fur on its neck, upper torso, fingers, and legs, forming black patterns on the legs that resembles ripped pantyhose. The tufts of fur above its eyes combine to form a single butterfly-shaped crest. The cream fur on its wrists and ankles becomes more round instead of fluffy, but the rest of its lower leg fur is replaced by the "pantyhose." Its ear fur now only covers two segments of each ear in fluffy bands.
It sheds its fur twice a year and has a soft, fluffy coat in winter. When the hot seasons end, the coat is replaced with one filled with plenty of insulating air for the cold weather. This fur can be used to make warm mufflers and hats. Lopunny is a timid Pokémon that will cloak its body with its ears or spring away when it senses danger, though is capable of unleashing superdestructive kicks with its lithe legs. Because of this, Lopunny is constantly monitoring the surrounding area. When Mega Evolved, a full-power whip swing from its ears can crumple steel plates.
Pokémon Mystery Dungeon: Explorers of Sky: Team Charm debut in their own Special Episode, Lopunny being the playable character. She is shown to be the fun-loving member of the group, even ending almost all of her sentences with hearts. The team hears about the treasure-filled Southern Jungle. They are advised to stay away by a Bellossom but the team continued on. They find a passed out Wigglytuff, who fainted due to hunger and give him a Perfect Apple, revitalizing him. They encounter Team AWD, who believes the team is pathetic. Before they enter, a Sentret pleads Charm to stop AWD, saying they were cruel to it. The team arrives at the dungeon's end, which holds an empty chest. AWD accuses Charm of taking the treasure and they fight. Wigglytuff appears to stop the brawl and reveals that the chest is a Ditto. The Bellossom and Sentret earlier were also him. He reveals he is there to guard a Time Gear and the teams leave. They later bribe Wigglytuff with a Perfect Apple to join their team.
Lopunny and its pre-evolved form share its category with Scorbunny and Raboot. They are all known as the Rabbit Pokémon.
Lopunny appears to be a caricature of a Playboy Bunny or other bunny girls as seen in popular culture. The bunny girl costumes of Playboy fame are still quite popular in Japanese adult media, which might explain Lopunny's coquettish cry and girlish figure. It is also likely based on a lop rabbit, or more specifically the Holland Lop. Regular Lopunny is possibly a fashion model wearing women's fur or faux fur-cuffed gloves and boots, while Mega Lopunny may be inspired by 1980's styled aerobics outfits. Due to the size and placing of its eyebrows, which could resemble antlers, it is possible it is based on a jackalope.
Lopunny is a combination of lop (a breed of rabbit with ears that flop over rather than stand erect) and bunny.