Nymble are not actually flying pokemon, and the folded limbs on their backs are legs, not wings. They are, however, incredible jumpers, who are more than capable of leaping through an open third-story window – a challenge they greatly enjoy, much to the chagrin of whoever is living or working inside.
Accounts abound from office buildings of spotting Nymble at significantly higher heights, which was for some time a scientific mystery, until it was proven that every building to give rise to a Nymble sighting had another tall one nearby. The wall jump, a common move in platform games, is said to have its origins in a Paldean game developer looking out the window, and observing one such Nymble jumping across the skyline, trying to climb as high as it possibly could.
Once they get inside, Nymble do not stop jumping, moving from lamp to floor to table far too quickly for human reflexes to swat, all with a loud buzz which leaves them impossible to ignore. To these pokemon, every indoor building is an obstacle course, and the efforts of people and the occasional pokemon to catch them a source of hilarious entertainment.
Nymble are unevolved pokemon, and can be kept away by keeping the window closed or spraying repel. But the former is no easy ask in a place without air conditioning on a hot summer day, and the latter, apart from its smell, may also keep away important working pokemon. Although experiments with Tarountula silk on windows have shown promise in keeping Nymble, a cheap supply which can withstand its opening and closing remains frustratingly elusive. And of course, Nymble are born adventurers, who often make their way into buildings where no countermeasures are available, for the simple reason that no one ever expected to see one there.