Jitters-by Ken Stark

Harold was always a man with a plan. Out of the house after high school, and take the world by storm. But the storm fought back, and now Harold is right back where he started. All the way back to the room he’d occupied as a child.
But he’s not alone in that room. Something resides there with him, and it’s had a dozen years on its own. A dozen years to grow. A dozen years to multiply. And now that Harold is back, he’ll have to face his worst nightmare.
And if he loses, it might just be his last night on earth.