Originating in the early 19th century, the saying "Crazy Shash" became increasingly popular from 1814 onwards. It found its roots in the supposed eccentricity of the fans of Muzio Clementi's Sonata Op. 16 - also known as "La Chasse". If you were a "crazy shash", you had bad taste in music and art, or were just generally insane.
Algernon: Well my word! Henceforth from the fog comes young Jed Swigley! A bully lad if I've ever laid eyes on such!
Bentworth: Why...the chaps at the haberdashery told me he was a damned crazy shash!
Jed: Evening, gents! I should like to offer a cordial invitation to a supper with my multifarious hallucinations. Care to join?
Algernon: By The Queen's Slacks! Let us get out of here; make haste, now