Parasyte: The Maxim

In the fall of 2014, NTV launched one of the most mature and philosophically rich horror anime of the decade — "Parasyte: The Maxim," where an alien parasite named Migi takes over not the brain, but the right hand of high school student Shinichi. The premiere on October 9 opens the story of the coexistence of two consciousnesses in one body: a boy striving to maintain his humanity and a creature studying human nature through his eyes.
The anime adapts the manga by Hitoshi Iwaaki and operates on the edge of genres: it features bloody battles with other parasites and quiet reflections on what it means to be human. The tone shifts from school life to cosmic horror, accompanying Shinichi's evolution from a timid teenager to a hybrid being capable of crying over the death of a puppy but ruthlessly eliminating enemies. The 24-episode format allowed for a complete adaptation of the manga with a cult ending.
If you watched "Tokyo Ghoul" and appreciated the metamorphosis of the main character, or "Fullmetal Alchemist" for its philosophical dilemmas — "Parasyte" offers a more concise and complete narrative. For comparisons with other "monsters within," watch "Attack on Titan" or "Dr. Stone."