The Metal Extractor extracts metal from metal spots on each map. The amount of metal you can extract per second is shown on each metal spot, with some spots giving more than others, especially contested ones.

Grunts are cheap units for protecting metal extractors from early raids.

Metal extractors are primary targets during early-game raids, and if destroyed, can stall an opponent's construction and give you the upper hand.

Metal extractors cost 3 energy per second in upkeep. Be mindful of this.

If threatened, metal extractors can self-destruct in just 1 second (compared to most units' 5), and deal just enough damage to kill low-health infantry or scouts standing too close.