Crystalline golem

The crystalline golems, or crystal golems, are constructs created by the storm giants of Ulduar. They look like men, only larger (and made of crystal), and serve the giants as workers, scouts, and servants. They can be found both in Crystalsong Forest and the Storm Peaks in Northrend. They are used to collect the crystals for the storm giant's experiments and to protect Crystalsong Forest.

In World of Warcraft
These creatures currently do not exist in the World of Warcraft.

Speculation
It is speculated that these golems may be the colossi seen inside Halls of Stone.

However, it is written that they were made by the iron dwarves.