When the signal came, there was nothing subtle about it: every radio telescope on the planet redlined. First primes, then simple arithmetic, then basic vocabulary, each burst richer than the one before. Finally humanity received the most complex message yet. Thousands of researchers and ad hoc internet communities raced to decode it. "Are you crabs yet?" Hesitantly, humanity replied, "No." "Oh," came the reply. "Sorry to bother you." Silence followed.