At the bottom of the homepage for the MAD website of www.madmag.com is a red “taskbar,” on which is a link for the DC Comics message board for MAD. In the forum “Other MAD topics” is a discussion of Alfred’s phrase “What, me worry?” which the magazine first rendered into Latin, in a 1959 issue as part of an inscription on a school’s bass drum, as QUID, ME VEXARI? but “corrected” on the cover of an issue two years later as an inscription on a Roman temple, QUID, ME ANXIUS SUM? Someone posting on that message board said the 1959 version was not correct, but I wonder whether the later version is incorrect too, since the verb (sum) is in the indicative, not the subjunctive. I’ve also tried to render it into other languages (I apologize for using a computer that doesn’t add accents):
French: Quoi, je m’inquiete? (with circumflex over the first “e” in inquiete)
Russian: Chto, ja nadojedat’?
Esperanto: Kio, mi malkvietighu?
Spanish: Que, yo me preocupe? (with inverted question mark and accent as appropriate)
I guess the closest you’d get in Japanese would be Nani, ore shinpai suru?, but it doesn’t have the same ring.
Maybe someone with a better grasp of street-Japanese can come up with something better.