Plate Core is the boss of the Stage 5, Asteroid. It is similar to Enigma in that it is a gunwall with many cores. It is encountered in the ruins of an old Bacterian Final base.
At first, you will have to deal with all three of the boss' parts, the large ship, the small ships, and the wall itself. The large ship is weak in its wings (the orange/brown things). The large ship can attack by either opening its wings and firing loads of homing missiles (pictured), or by shooting blue bullets from the holes in its wings. If the large ship has no wings, it will fire large blue bullets constantly, taking about half a second to reload. Attempting to bypass it will force you to deal with the smaller ships it spits out, which fire large spreads and can be undodgable if you haven't killed the large ship yet. After the large ship is destroyed, the Plate Core will start generating swarms of small enemies.
This boss is very easy to time out, due to the sheer number of targets to attack in this battle.