Irish English: What is cat melodeon?

Don't shoot me I'm only the piano accordion player!

Cat (a): dreadful, no good, awful, very bad. Or for a more emphatic version, Cat melodeon (Sounds like 'melojen')

Bernard Share’s dictionary of Irish slang Slanguage quotes Victoria White in the Irish Times calling cat melodeon “the greatest expression in Hiberno-English.” It is used to express general disappointment in the quality of something: the food is cat in that place.

Where does Cat Melodeon come from?

The Cat Melodeon players

In his book on Irish traditional music Ciaran Carson suggests it is a joking reference to musicianship of piano-accordion players (who often refer to their instruments as melodeons) to play two notes at once.  Source   As the nephew, of a fine melodeon player I think this is cat altogether  -  you throw in altogether for emphasis, by the way.

When was it first used?
Strangely some dictionaries cite the first use in print as being in the 1980s. This is decades after I first heard it - my guess is that it has been common in speech for at least a century.

How is it used?
I have most often heard it as a yelp of protest: That film was cat/melodeon!/Cat altogether!'