Zhuan Zhu was an assassin

Assassination

To carry out an assassination is "to murder by a sudden and/or secret attack, often for political reasons." Alternatively, assassination may be defined as "the act of deliberately killing someone, especially a public figure, usually for hire or for political reasons."An assassination may be...

 in the Spring and Autumn Period. As Prince Guang (later King Helü of Wu

King Helü of Wu

King Helü of the state of Wu , a state in ancient China, was initially known as Prince Guang . He reigned towards the end of the Spring and Autumn Period.-Biography:...

) wanted to kill King Liao of Wu

King Liao of Wu

King Liao of Wu , also named Zhouyu, was king of the state of Wu in the Spring and Autumn Period.-Biography:...

 and take the throne himself, Zhuan Zhu was recommended to Prince Guang by Wu Zixu

Wu Zixu

Wu Yun , better known by his style name Zixu , is the most famous ancestor of people with the surname of Wu . All branches of the Wu clans claim him as their "first ancestor"...

. In 515 BC he managed to kill King Liao in a party with a dagger hidden in a fish. He was killed after he had completed his mission.
In folklore, the dagger he used to kill King Liao was named Yuchang (魚腸), or "Fish intestines", because it was small enough to be hidden in a fish.