What a young movie!

Seems like the horses story ended

Small clarification, he gets stuck in the swamp of despair basically. He only gets stuck and dies because he loses hope. Atreyu tries to cheer him up and give him hope, and it's that scene that's depressing AF. It's like something out of old yeller.

I think the OP is from the movie Signs?

Well, do you recall how fulfilling the wishes demands a sacrifice of Bastian's memories and self?

One might alternatively phrase that as wish fulfillment, if one was tricky writer sort.

One might also note that the Story demands Bastian pass it on to another child if he wants his own memories back. Once he realizes he is not willing to give up his last memories of his father.

Passing to a new host once it has drained Bastian of what it wants and his defenses prevent it from gaining more, as it were.

A successful parasite is not one that kills its host, after all, it's one that spreads and grows.

And then it evolves and spreads to a new, American movie going population where that message isn't profitable so it just becomes a standard chosen one story.

Demons are often defeated with water. Some can't cross running water. It's an ancient trope.

It's a very common theory but not explicit. It all makes perfect sense though

It's easily his best film. Everyone shits on it because it was another "twist" while completely ignoring the excellent dialog, acting, character building, and theme. At its heart, it isn't a story about an invasion. It's the story of a grieving family leaning on each other for support after a tragic loss.

Gibson's character had been outwardly the strong, moral man of faith at the center of his family and the community. His wife's death pulled him into deep despair that had left him a broken man. He no longer had hope for the future and had stopped providing hope and comfort to his family and community.

Throughout the film, you see not only his grief over the loss of his wife, but everyone else's grief over losing him as a fixture of compassion, comfort, and grace. The story is about his faith and hope being restored. The events that lead to that involve hostile invaders, but they're just a mechanism to tell the story of grief and healing.

There's a scene with Phoenix and Gibson whispering quietly for like 10 minutes about belief and fate with no action - just great acting and dialog. There's a scene where he breaks down crying over his family and how cruel he's become due to his fear and hopelessness while simultaneously eating a meal.

And in the end, many of the aspects of his normal life that contributed to his grief, annoyance, and fear were key to his family's survival. He accepted what life had thrown at him, and was able to heal.