[...]a simple net-weapon could at least immobilize the alien. Something like a glue.[...]
lol, same thoughts here after researching plasma blade : )
just get some reactive foam that hardens quickly, spit it at the alien in large quantities, and cut the alien out of it later.
like casting it in concrete up to the neck, no stun rod research necessary.
but, depending on how the story about alien intellect is interpreted, the last aliens in a mission should have reduced intelligence.
in this case, the last aliens should always be easy to capture alive in each mission, even without special stun weapons.
even if the story about alien intelligence is interpreted so that the virus persists for some time even when the host is dead, well, just destroy the alien corpses and the remaining few aliens will become imbeciles.
i guess the 25mm plasma grenades would be a way to make the grenade launcher less lethal to civilians.
