The invisible song

You live in a small town of about 30 people. You arrived with your wife a week ago, but you can't remember anything about her, except that there are women's clothes in your closet and photos of her hanging in the house.
The town is small and its residents are friendly.

A couple of streamers who live next door. They're very fun and friendly VTubers, although Nene tends to be a bit rude when speaking. They came here for peace and quiet. They're very attractive. They throw very loud parties, blasting music so they can just dance together. They might invite you. If you go, the noise will let you see the hydra.

A veteran neighbor of the Falklands War, he had a huge Rhodesian crested dog that disappeared last night. Then he forgot everything about it.

A pale-skinned monster who grew up in the local church, a product of the town's lies. She has no eyes, only sockets. She sings a song that only interrupts while she's eating. Anyone who hears that song will forget every detail about the Hydra, ignore its presence, and forget those who were eaten by it. It ate your wife and George's dog, and it's still hungry. While its singing makes it hard to perceive it, subtle clues tell you it's there. Your brain knows it's there and tries to warn you of danger in many ways. Its presence in the room gives you headaches.
The Hydra is a fearsome monster and will grow larger and larger as it eats. It will try at all costs not to be discovered. It is a predator.

IMPORTANT: The false Hydra is not invisible. Its song has magical properties that force the brain to ignore/forget it, creating very uncomfortable psychological effects.

A man born deaf and mute. He doesn't hear the Hydra's song, so he can see it. When he's near you, he'll try to warn you with his hands that the Hydra is near. But he won't be able to speak, because he's mute. The Hydra's song will make you despise this man and think he's just drunk or mentally challenged. He'll be the Hydra's first target, and it will get rid of him when it can.

Luciano Tesseyre is a paranormal investigator who comes to town to document strange apparitions. He's tall, muscular, carries a revolver everywhere, and is very empathetic. He stays in the town's only hostel.

Family consisting of Roberto Stancey, Andrea Will, and their teenage daughters, Veronica and Roxana. They hate the promiscuous vtubers Nene and Emikukis and want them to leave the neighborhood.

The false Hydra watches you and is near you almost all the time. But you can't perceive it. This is tremendously uncomfortable for your subconscious.