Isn't this it?

I want that face to split like a parasitic tree. Keywort, it will be difficult.

I think you saw it as a parasitic K-drama, but just watching it makes me nauseous. Just watch the original animation. That's an even better masterpiece. I highly recommend it. It's not overly action-packed, but the action plot is quite believable, and the male protagonist is an alien parasite absorbed into a human body. There is no process of psychological change or a romantic love story at all, and it is an animation work that focuses solely on the story, like a lecture. Drawing? Let's see what there is to say.