Zamzummims

a race of giants; "a people great, and many, and tall, as the Anakims" (Deut 2:20; 2:21). They were overcome by the Ammonites, "who called them Zamzummims." They belonged to the Rephaim, and inhabited the country afterwards occupied by the Ammonites. It has been conjectured that they might be Ham-zuzims, i.e., Zuzims dwelling in Ham, a place apparently to the south of Ashteroth (Gen 14:5), the ancient Rabbath-ammon.

EBD - Easton's Bible Dictionary