I found weird structure, what is it ?

After quick Alt+Tab, opened up Google, i was surprised that this structure is an event boss fight, known to be painful, since the exterminator has different combination of weapon protecting it. That means for certain combination of weapon firing at you (that's why the word "modular" is in the name, it comes with different weapon combo), you need certain strategy to survive. Short version of it, its your luck that determine whether the fight will be less punishing or hurt like hell

What is the purpose of the structure ?

Turns out it was meant for late game content, that require key. This key is acquired through promoting one of the class (Engineer, Driller, Assault, Scout). The reward is overclock module for your weapon or you can choose cosmetic.