أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
It means that the other person is talking non-sense.
Like the dialogue in Indiana Jones & The Last Crusade Movie; when Indiana tried to fake a Scottish accent to pretend that he's from Scotland, but it was to obvious for the actual man who came from Scotland and he said to him: "Yes, and I'm Micky Mouse!"
This is not a familiar idiomatic expression. However, it can be used for unrealistic pop and show.
In Persian language a similar expression is used, " Pidram Sultan Bood". (My father was a King).
I see no idiom here, just a simple statement
In French, that would be : "Bien sûr, et moi, je suis Napoléon !" ;)
