Arcane golem are magic-powered golem creatures used by mages and wizards as sentries. Apparently, they run almost entirely off of control-based magic, which can easily be disrupted by its caster's death with the result of many arcane guardians becoming hostile rogues in time.
They are a product of both mechanical engineering and arcane enchantment, and as such can be classified as both mechanicals and elementals. In-game, arcane guardians have one or the other of these creature types.
- - Boss in Karazhan