Destroy Fireballs

364 per kill One, two, and three stars: 3, 6, and 9.

Any map.
The wiki's high-score map is Stella Montis: Cultural Archives, Medical Research, and both Robotic Sandboxes. Shredders use those same rooms.
An Anvil can break the armor in one shot. A Hairpin also destroys one in a shot, but only after it opens. A Hullcracker is for the Shredders.
A second Fireball killed by the leftover fire does not count.
Patch 1.26.0 removed the double points on a major map condition.