A giant outside monster with a huge spotlight emitting over the player.
To preface I know nothing about how to mod or how difficult things are to implement, I just want to get this idea out there since I didn't see any other post about this kind of entity. It's an idea that takes parts from that one suggestion in Moonsneer's thread and Daszombes' video where there's a gigantic creature that hunts with a spotlight. The image used of the creature is Trevor Henderson's Light Head.
I've always thought this type of thing was cool as hell ever since In Sound Mind, and seeing both the video and the message I wanted to give it a go to flesh out the creature a bit.
The 3 behavior ideas are taking different aspects from the game (and the thread/video) and remixing them for the outside.
-Radar is stalking, surprising, and scaring the shit out of the player suddenly with a beam of light.
The idea of a radar is based on the spotlight creature being a mechanical being like the coil-heads rather than a living breathing being, so having a radar over its hunched back was the initial premise of this whole thing.
-Constant Search is more basic enemy pathing and being a constant threat similar to forest giants.
-Lighthouse is just area denial and being a nuisance when trying to travel back and forth for loot
The video is my meh attempt to showcase what the hell I'm talking about. I'm not the best when it comes to video editing so it's mostly an amalgamation of stock sound effects and raising contrast but hopefully it should get the idea across.