The Duetto Buffo di Due Gatti – which translates roughly as ‘humorous duet for two cats’ – is an entertaining performance piece. The “lyrics” consist entirely of the repeated word ‘meow’.
No-one is 100% sure who wrote it. It’s often attributed to Gioachino Rossini but was not actually written by him. It’s a compilation written in 1825 that draws on his 1816 opera, Otello. Even the compiler is shrouded in mystery as the name G. Berthold appears to be a pseudonym.
I think this is one of the best versions on the internet, partly because it’s so beautifully done but mainly because the dark-haired boy on the right is clearly having a really hard time keeping a straight face!