The Eldritch Construct is one of the four champion boss mobs found in The Outer Lands. It has an extremely large amount of health (250 half hearts), but it still seems like an underwhelming amount to its size. It looks like a massive iron suit of voidmetal armor or crimson armor.
It is counted as a boss mob as a purple health bar will appear at the top of the screen when encountered. It will move about quite slowly but does a massive amount of melee damage. When "killed" it will instantly heal back to full health and will have its head replaced with an eldritch eye, it will not need to be battled again once you kill its second stage.
the name it is given is random in-game, and the name accounts for it ability, for example: "Armored Eldrich Construct" takes less damage. also, if you deal a blow that kills it in its first stage in one hit, it will become 'Enraged' and have EXTREMELY rapid regeneration.
It is not affected in any visible way by wand foci as it takes no damage from most and is not knocked back by most as well. Secondary effects still seem to take effect.