How to respond to a masked ball or a fancy dress party?

We do not balk or negotiate with the mistress of the house to obtain a safe-conduct
You don't arrive without your costume on the pretext of lack of time or forgetting
There is no shortage of originality...

But then how do we do it?

Our good education therefore reminds us to comply with the requirements stipulated in the invitation.
I would even add, let's go hard; Americans say “go big or go home” (translate go big or go home... rather explicit!).
Remember also that the success of an evening is due to the kind contribution of everyone...
And if it's so unbearable, well, there is still the option of politely apologizing!