Goosebumps (1995) : 3x17

Nicholas is at first optimistic about getting a baby sister, but his friend tells him all the cons. When his parents arrive, he meets his sister Grace. Though, Grace is no normal baby. She makes a block message that says ""Only me"". And she pukes on Nicholas when he goes to comfort her when she is crying in the night. Nicholas can take a hint when she eats his pet. Nicholas knows that Grace wants to be an only child. And she'll do anything to get rid of him. So when their parents leave Nicholas home alone to babysit Grace, Grace does some real bad things. Scary things. Evil things. Things that COULD make her an only child...