Kiseijuu: Sei no Kakuritsu

The 17-year-old Izumi Shinichi lives with his mother and father in a quiet neighborhood in Tokyo. One night, worm-like aliens called Parasytes invade Earth, taking over the brains of human hosts by entering through their ears or noses. One Parasytes attempts to crawl into Shinichi's ear while he sleeps, but fails since he is wearing headphones, and enters his body by burrowing into his arm instead, taking over his right hand and is named Migi.