Agnes Tachyon was a Japanese Thoroughbred racehorse and a leading sire in Japan. His major wins include the Satsuki Shō, and the Yayoi Sho. He ran undefeated from 2000 until 2001, and was widely anticipated to win the year's Classic Triple Crown. However shortly after winning the Satsuki Shō, a bowed tendon suddenly ended his racing career, leading to newspapers referring to him as a 'phantom' Triple Crown winner.