Have I said how much I hate February and losing 2-3 days of dev time? Yeah, I know I have. Which means that when this morning rolled around, I realized I was due to post an update. So, this is mostly written in between projects during my day job (which is also impacted by deadlines missing 2 business days).
So, how about that ending? As someone in the comments called it: "Chekhov's Grendel". We've always tried to drop little things early on as hints for later revelations or moments, like the UPS van, the missed text message from Naomi in N&T. The only thing we didn't really telegraph was Marisa's secret in TID, and even that had some background build-up, but not in the expected way.
I think we've done it enough that folks on the Discord are looking for clues that are really just background noise meant to make the world feel lived in. There's a certain level of world building a writer has to do to make their story exist in a tangible environment: mentioning family or friends, or just talking about simple things like Girl Scout Cookies. If your characters don't exist solely to push the narrative, then they feel more like actual living people.
On another tangent:
While going through my collection of old video games, trying to mine some story/gameplay concepts for future gold, I unearthed an old PS2 game that I forgot I'd owned, much less played, well over a decade ago: Siren (or Forbidden Siren). I bring this up because it struck me that TOXICity borrows some elements from this game, as well as all the other movies/shows/games I've already credited. It's not a strong connection, but the isolation, the limited visibility, and the human-like threats to normal, everyday people all come across as at least tangentially influential. Probably a lot of horror games from that era seep into our work, more than even we realize.
Also, I recall the PS3 remake being nerve-wracking.
Thanks for your interest and patronage,-Kinderfeld