Parasyte -the maxim-

Parasitic aliens invade Earth, stealthily taking control of humans by entering their brains. These relentless entities dominate their hosts and can shapeshift to hunt unsuspecting victims. High schooler Shinichi Izumi becomes a target but narrowly escapes full possession; instead, the parasite lodges itself in his right hand. As Shinichi grapples with this unique bond, he must navigate a world where these creatures threaten humanity, all while coming to terms with his new reality and the implications of sharing his body with a relentless alien entity.