Parasyte -the maxim-

Sinopsis

Mysterious worm-like parasitic aliens descend upon Earth, infiltrating humanity by burrowing into the brains of vulnerable targets. These insatiable beings take full control of their host, morphing into various forms to feed on unsuspecting prey. Seventeen-year-old high school student Shinichi Izumi becomes a victim when a parasite attempts to enter his ear but is thwarted by his headphones. It instead burrows into his right hand, failing to reach his brain. The parasite, named Migi by Shinichi, is forced into an uneasy coexistence with him. They retain separate intellects and personalities, leading to a strange symbiotic relationship.