The first one being the episode of the rugrats "In the dreamtime" that episode used to make me cry when I was little and if I saw it was on I would run out of the room screaming, it gave me nightmares. It's an episode where Chuckie, one of the main characters, is having a bad dream, and at several points in the episode he comes across one of his friends or family (Tommy, Stu, Chaz) turned away from him, so he taps them on the back and they turn around and with distorted faces say "I'm not (insert name of who ever turned around here)!" Lots of Rugrats episodes spooked me, but that one I flat out hated, I'm 20 years old now and still don't like it.
Next being a couple of children's books, I forget the author, but they were called "There's a nightmare in my closet" and "There's something in my attic." I think. Anywho, these were straight up children's books about things that go bump in the night, it had pictures of the monsters, those are what scared me, I used to take them and hide them alot because looking at them scared me. I still have the books actually, though they reside in my little sister's room now, she's 9 and laughs when I tell her they used to scare me, she thinks the monsters are cute and the story is funny (Which, they really are cute stories, I was just a scaredy cat.)
The last one was a doll named "Amazing Amy" I thought this doll was evil and I was terrified of robotic things anyhow, I didn't like how this doll could talk and seemed to know when I would feed her the wrong foods or dress her in clothes she didn't want to wear. My big brother would often find her hidden in the house and would sneak her into my room at night and place her standing by my doorway facing my bed. Years later another doll named "Amazing Ally" came out, she was alright until she told me and my sister she needed new batteries. We taped her up in a box and stuck her in the top corner of the closet. Then just a couple years ago we got my youngest sister (she was 7 at the time, 9 now) the "Amazing Amanda" doll. Her robotic face has all these things under her doll skin that cause her to have facial expressions, but when we first turned her on she malfunctioned and all the robotics began to move at once causing her eyes to open and shut, her mouth to open and close, and her entire face to just move awkwardly as if she had something trapped under her skin. It made my sister cry and we had to take out it's batteries. Long story short, robotic dolls are spooky.
I hope these stories entertained, I just recently discovered your website!
I remember those books. I wish I still had my copies.
They were by Mercer Mayer. Though these days I think he's best known for his Little Critter series.
I remember that episode of Rugrats, I was in my late teens when I happened to come across it and it really did send a shiver down my spine. I think that premise (a person you know and feel safe with revealed to be some kind of horrible twisted doppelganger) must be quite common, I remember having a similar, terrifying dream when I was younger.
I remember that Rugrats episode, too. Though I'm not scared of it anymore due to "I'm not Sonic, I'm my original character, Blonic!"