Can you explain the context? My first thought is a themed party or event. Is this correct context?

In English, please.

Hey Junji, Check out this answer: What have you come as is what people in the U.K. ask their friends when they do something peculiar,act off, or anything else pertaining to an attitude or behavior. *friend walks in wearing a bum bag, stilettoes, and ear muffs* "Oh, Lord! What have you come as?" I hope it helps. See you in my classes.

頑張れます… This is inquirers into a few different states of being: - mental state: have you come as a friend or foe? - intent: supporter or antagonist? - presentation: usually in reference to a costume (eg at Halloween) “that’s an interesting costume, what have you come as?” It’s kinda of a clunky expression that I would only every use at a costume party. More natural would be ‘why are you here?’ ‘What have you come for?’

In which language do you want the answer?