Juggernaut Golems are rather rare constructs that can only be hit with +2 weapons and have a high resistance against all physical damage except Crushing.
Like Stone Golems, they have the ability Golem Slow which is similar to the Slow spell.
They can for example be encountered when taking the "I wish to be more experienced." option of Limited Wish at a high enough level.
The Juggernaut Golem Manual actually produces something closer to an Iron Golem, so it was misnamed.