Being an expert on the different fields of science, Lisa Loud could most likely explain to you the concept behind the "Many Worlds" theory. A theory that states, that our universe is just one of many in an infinity number of realities. Realities that are similar to each other, yet still differ. May it be in small things like the fact that a certain president lost the election by a certain number of votes or something big, like people being born with their butts on their heads. Which, thinking about it, would not necessarily affect the looks of many people in our world.
And somewhere in this sea of worlds, there was one world, where for Lisa Loud and her family life was overall very similar to what it is in her current universe.
Lincoln was born a boy and as middle child of a family of eleven (13 if you count the parents), Luna Loud discovered her love for rock in a faithful summer in seventh grade and the events of an episode called "No such luck" still sucked hard.
But in this world, one huge difference to the "regular" Loudverse existed. You see, in this world Royal Woods actually is not part of the United States, but rather of NUR, the "Nation of United Regions". In this world, a group of international criminals referring to itself as "Team Nostra" exists and the Loud family doesn't own four pets. Well, correction. They primarily own four pets named Charles, Walt, Geo and Cliff. Only that Charles was not born an American Pit Bull Terrier but as a Houndur, Walt is a Starly. Geo a Dedenne and Cliff is a midle aged Purrloin. And those are not the only adorable yet equally bizarre creatures existing in this world.
Welcome, boys and girls. To the PokeLoudworld.