A strange adventure befell me while I was playing my Sonata...

A strange adventure befell me while I was playing my Sonata in B flat minor before some English friends. I had played the Allegro and the Scherzo more or less correctly. I was about to attack the March when suddenly I saw arising from the body of my piano those cursed creatures which had appeared to me one lugubrious night at the Chartreuse. I had to leave for one instant to pull myself together after which I continued without saying anything.