I can't fucking remember

Ok so a couple of years back i read a manga about some alien or some shit and it was in this guys hand, and he had to fight other aliens like him that were inside other people. The alien type thing had to have a host or it would die and it couldn't leave it's host or the host would die too. anyway, there was like crazy badass creature dogs and shit so... uhh anyone know the name of what im talking about?


sorry for the shitty description.

bump

it was parasite nevermind