Terror

It is not difficult to detect the horror genre in anime. Usually, if there are ghosts, monsters, gore, and creeps, then it is likely that you are watching a horror series. Heavy gore and bloody violence is a common trait. The most important factor for a show to be considered a horror is its ability to scare and scare people.

Parasyte

Is a Japanese science fiction horror manga series written and illustrated by Hitoshi Iwaaki. Based on the horror and science fiction manga (of the same name) by Iwaaki Hitoshi. 17-year-old Izumi Shinichi lives with his mother and father in a quiet neighborhood of Tokyo. One night, aliens with the appearance of worms called Parasites invade the Earth, seizing people's brains entering through their ears or noses. A Parasite tries to enter Shinichi's ear while he sleeps, and fails since he wore hearing aids. But he enters his body digging his arm and seizes his right hand, which is renamed Migi. As Shinichi was able to prevent Migi from continuing his journey to his brain, both beings retain their intellect and personality. As the duo meets another Parasites, both are compatible with their strange situation and gradually form a strong bond, working together in order to survive. This gives them an advantage when fighting against other Parasites that attack the couple when they realize that Shinichi still keeps his brain intact. Shinichi feels obliged to fight against other Parasites, which devour humans as food, with Migi's help. 

Another

The story focuses on a cursed class and on the threads of destiny that lead all the students of it to death. A girl named Misaki had been going to class for 26 years. Good athlete, popular, everyone liked her, the best grades? But one day he died leaving a huge void in his classmates. These, determined not to forget it, continued to act as if Misaki was still alive until graduation. Years later, in the spring of 1998, a boy named Koichi Sakakibara is transferred to that class so as soon realizes that there is something strange there, especially with that Misaki who always sees the background of the class drawing alone and who wears a patch.