Someone thought of the idea for this.
Someone thought that this was a good design and a good idea.
Enough people thought it was a good idea to start designing it within the team.
Enough people at Gamefreak thought this thing looked good enough to okay it.
People designed a 3D model for it. A battle model, all those Amie Animations for it.
People gave it a typing, a movepool, a pokedex entry.

This thing bears the Gamefreak Seal of Quality.