I never really feared something happening or a specific object when I was a kid, but I suffered from AIWS (
Alice in Wonderland Syndrome) from when I was 5 to 16 years old. I've thankfully outgrown it, because it was always a terrifying experience.
Basically, I'd wake up and experience extreme distortion of my visual perception. The far wall of my room would look like it were 50 feet away, and the ceiling would look to be 30 feet tall. My hands and arms seemed to be bowed and elongated. The hallway outside my room was huge and loomed over me. My perception of time was often skewed, also-What felt like a half an hour was really only 5 minutes, and on rare occasions 20-30 minutes would go by in what felt like minutes.