“Alien Nine” (2001) IMDb
Three Tokyo girls in sixth grade are “elected” by their classmates to serve as the school’s standing army against alien invasion. Their chief weapon is a set of parasitic winged batrachian extraterrestrials. Their duty is quite safe, since the parasites will go into panic mode and kill any attackers if the girls fail to capture them properly, but one girl is grossed out and terrified.
Yurui SF psychoanalytical horror. An effective treatment of the “slimy aliens as puberty” metaphor. Based only on the beginning of a manga, unfortunately. Minor Gainax involvement.