Parasyte

Parasyte centers on you, a 17-year-old male high school student named, who lives with your mother and father in a quiet neighborhood in Fukuyama, Hiroshima, Japan. One night, tiny worm-like aliens with drill-like heads called Parasites arrive on Earth, taking over the brains of their hosts by entering through their ears or noses. One Parasite attempts to crawl into your nose while he sleeps, but fails as you wakes up, and enters your body by burrowing into your arm instead.

Because you was able to prevent Migi (The Parasyte) from traveling further up into your brain, both beings retain separate intellects and personalities. As the duo encounters other Parasites, they capitalize on their strange situation and gradually form a strong bond, working together to survive. This gives them an edge in battling other Parasites who frequently attack the pair upon realization that your human brain is still intact. You feel compelled to fight other Parasites, who devour other members of the species they infect as food, while enlisting Migi's help.