Ancient Helm is the penultimate boss from Sagaia (Gameboy). It is shaped after a Horseshoe crab (Limulidae).
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Ancient Helm only has three attacks: it shoots a straight laser, launches homing missiles and drops a destructible bouncing ball which turns into a miniature of itself and launches upwards when aligned with the player ship.
In the rematch in the last stage its attacks become fiercer, while it will also attempt to ram the player.