I think I get it now. The first host is a small insect, probrably an ant. Then it moved to bigger hosts like the wasp and cat. This is a long process, that's why the Detective said there are an [unsually high number of dead insects in the room]. When this monster move to the next target, its old vessel split open in half and the monster will grow bigger while keeping a feature of its previous hosts. The cycle continues and that's why in the end it look like a big clump of different insect/animal parts.
About the girl, I think it's the other way around and that she's actually the real owner of this house, not the University boy. The story he tell the Dectective is a lie, it was the monster in him talking. The truth is, the monster eventually get to her cause she lives in the same house. Then it used her body and went to the party, take the University boy home, transmit itself to him via sexual contact. The rest is the begin of the manga where it hunt for the next host.
About the monster's origin, it is mentioned that this is an old house so I speculate that thing is some kind of insidious entity that are either born over time due to the house's negative energy or revived from its slumber through some coincidences?
I think I get it now. The first host is a small insect, probrably an ant. Then it moved to bigger hosts like the wasp and cat. This is a long process, that's why the Detective said there are an [unsually high number of dead insects in the room]. When this monster move to the next target, its old vessel split open in half and the monster will grow bigger while keeping a feature of its previous hosts. The cycle continues and that's why in the end it look like a big clump of different insect/animal parts.
About the girl, I think it's the other way around and that she's actually the real owner of this house, not the University boy. The story he tell the Dectective is a lie, it was the monster in him talking. The truth is, the monster eventually get to her cause she lives in the same house. Then it used her body and went to the party, take the University boy home, transmit itself to him via sexual contact. The rest is the begin of the manga where it hunt for the next host.
About the monster's origin, it is mentioned that this is an old house so I speculate that thing is some kind of insidious entity that are either born over time due to the house's negative energy or revived from its slumber through some coincidences?
This is just my takes though lol.