|There are some really nice ideas in this story such as a child being the protagonist (always unsettling in horror) and the use of a child's bedroom as the setting. Instantly evoking childhood fears that most of us had to deal with when we were young.
In terms of your ideas for this story, I have no issues. There are some excellent concepts which inspire a fearful atmosphere and I particularly like the description of the demon as an ovoid mass.
My main issue comes with the way it is written. You start well with an excellent description of Ollie in his bed being terrified by the presence in his room but then you launch into long segments of speech with no dialogue tags and no descriptions to seperate them. Unfortunately the text became quite tedious in these parts and I was left wondering as to how the characters were feeling and what they were doing.
An example of this is the conversation between John and Anne at the start:
Anne woke up, sweating. “John, there’s something---someone in this house! Wake up!”, she shouted.
“What? That’s impossible.”
“I saw it in my dreams. It was evil, John.”
“Come on, Anne.”
“In my dreams I asked it, “Who are you?” It said it was a visitor but I knew it wasn’t. So I said, “What do you want?” It said, “Him.”
“Him---who?”, John asked.
“Him, the “little” one, it told me.”
“Don’t you dare not believe me, John!”
“Alright. I will take a look.”
“I am coming with you. I know that there was someone else – awake – in this house. I can still feel it. As a matter of fact, I feel it's presence all the time.”
“You know - I "know". We must go to Ollie’s room first.”
“Look. The door is closed! He never likes it closed.”
“Open it, quickly.”
“Oh He’s in bed. He’s sleeping peacefully. Relax, Anne.”
“John, there is something in there with him.”
“What are you talking about?”
“I can see it; dark, eerie - it is right there, in the corner of the room, on the ceiling. Turn the lights on, John!”
“OK. See? There’s nothing there. Nothing.”
“It was there, John.”
“But how could it have disappeared so quickly, whatever it was?”
“I can still feel it’s presence...”
“Anne, there isn’t anything. Come on.”
“Come on. Let’s go to bed. He’s OK.”
- All of this happens with no descriptive elements telling the reader what is happening. Some moments could have really used some more depth and would answer such questions as how they were feeling as they made their way to Ollie's room? and what Anne saw when she looked inside?
I liked the concept of the tale and what you were trying to do. My main issue with this piece is the technical aspect. By better combining descriptive elements and character interaction you will improve the flow and enjoyability of reading it. Instead it just seems to be seperated into chunks of dialogue and descriptive elements. In some regards it feels more like a script than a literary piece.