Si'um
Si'um, also Siium, or Sium was the 18th Gutian ruler of the Gutian Dynasty of Sumer mentioned on the "Sumerian King List". According to the SKL, Si'um was the successor of Yarlaganda, and the last king of the Gutians before Tirigan.
A tablet is known, dated to c. 2130 BCE, mentioning the allegiance of Lugalanatum prince of Umma to Sium, King of the Gutians.