WMG: Dengeki Sentai Changeman
Gyodai's enlarging beam is how his species reproduce.
His species reproduces through external fertilization: the female lays eggs and the male use his beam to fertilize them/help them develop. That's why Gyodai don't need to be summoned after the first few times: he has associated the Power Bazooka being fired to a mating signal and is thus eager to do his work. This also explains why he is so exhausted afterwards. Also, this medicine the Gozma develop in #13–14? Basically alien viagra