Rayfly

Rayfly is a large Mechaniloid boss that is fought in Mega Man ZX. It hovers above Vent or Aile and drops three boxlike Bounce Cannons to the floor at a time. Destroying the Bounce Cannons is the only way to damage Rayfly, as it hovers out of reach of Model X's weapons. After it is defeated, Vent/Aile find themselves unable to destroy it. Giro appears then and slashes it with Model Z's saber which makes Rayfly crash to the ground and explode. 

Bounce Cannon
Bounce Cannon is the enemy that is dropped by Rayfly. It appears to have two different varieties, as only the one with the blue gem is able to fire. Destroying these enemies will cause damage to Rayfly.