Like most golems, the ice golem is an automaton, attacking only when commanded.
Ice golems have the ability to move and climb on ice very well, without slipping, sliding, or risking any harm. They can also release shards of ice from their bodies in a burst, affecting all those around them.
Ice golems, like most golems, are immune to magic. However, ice golems are affected by fire magic normally, and cold damage actually mends them.