An attack where a ridiculously large number of missiles are launched from one fighter jet or robot at a target or targets, regardless of tactical necessity. It's often characterized by the missiles' twisting, turning and crisscrossing contrails, emphasized by the missiles or beam weapons firing along trajectories that are at an unlikely angle off of their target before making sudden turns in order to hit it (an effect that's been dubbed Roboteching in the West).
Named after anime artist, animation director, and producer Itano Ichirou, and primarily comes from the anime franchise MACROSS and its first series released in the early 80s, with its origin series lending the additional name Macross Missile Massacre. The sub-effect of 'roboteching' is named after MACROSS' westernized equivalent in ROBOTECH.
