The Ancient Helm is a Horseshoe crab. Only appearing in the Sagaia game.
First encounter Edit
Attack patter consists of a big laser from its eye, two homing missiles from its body and small bouncing orbs dropped from its tail, which turn into small horseshoe crabs that go upwards quite quickly, attemping to crash into you. Hopefully you can destroy the orbs.
Second encounter Edit
Now it has changed to two big lasers from its eye, two pairs of missiles (making a total of four), a ramming attack and recycles the egg attack from the first encounter.
Considering most bosses in Sagaia are somewhat easy, this one probably is one of the hard bosses in this game, if not the hardest, specially the second time you fight it.