Brigadoon
/ˌbrɪɡəˈduːn/noun
In allusive use. A place, person, or phenomenon likened in some way to Brigadoon, especially on account of its mythical or idealized nature, its (romanticized) Scottishness, or its rare, fleeting appearance or occurrence.
Origin
1960s; earliest use found in The Times. From Brigadoon, the name of a fictional Scottish Highland village which materializes for only one day every hundred years, in the 1947 musical of that name by A. J. Lerner and F. Loewe, which was the basis of a popular film adaptation of 1954.