Major spoiler to follow.
I’m trying to figure out how much sense can be made of the creature’s actions as a series of trades. The way I reas it, it goes like this:
Callie offers food, the creature returns jewelry in trade.
Callie returns the jewelry, apparently rejecting the trade, so the creature offers a larger pile of jewelry in her bed.
That trade is apparently accepted.
Now the creature offers Daniel. But nothing is ever offered in exchange so the creature takes Daniel back–and maybe? is miffed.
The creature offers Walter, now dead. (Is he dead because the creature is miffed?) Nothing is ever given in exchange so the creature takes Tricia.
Callie offers herself for trade, the creature offers the fetus in exchange, Callie renegs, and in retaliation the creature takes both her and the fetus back.
Did I miss anything? Read too much into anything?