The Bubble Hat is a form of toque. It was first introduced in the late 1950s as a sort of puffy tam or beret and the rounded crown was fairly modest in size. By the early to mid 1960s it became the larger more exaggerated bubble form we commonly think of in regards to this style. They were sometimes completely covered in feathers, the later styles were often more stark and sculptural to reflect the mod ethos. They either had small brims or, especially in the later styles – pioneered by the space-age designs of Pierre Cardin and André Courrèges – no brims.
See also: Toque