How do you imagine the coming alien invasion? Movies have been all over the map with this question, though in recent Japanese films such as Takashi Yamazaki's "Parasyte" duology (2013-14) and Daihachi Yoshida's "A Beautiful Star" (2017), extraterrestrial visitors take a human form.
This is also true of the aliens in Kiyoshi Kurosawa's cleverly metaphoric sci-fi "Before We Vanish," which premiered in the Un Certain Regard section of this year's Cannes Film Festival. They invade human hosts to prepare for an invasion that will wipe out the human race, save for a few specimens to be kept for study purposes.
One twist is that we never see the aliens in their original form. Another is that the aliens are ignorant of what makes their hosts tick and try to remedy that situation by acquiring a human "guide" and taking what they call "gainen" ("concepts") — deep-rooted beliefs about family, possessions, self, work and love — from unwitting humans with the touch of a finger to the forehead. The giver is left unharmed, save for the loss of said concept. This turns out to be a very big deal indeed.