Goosebumps Most Wanted: Planet of the Lawn Gnomes.

Jay is not a particularly good kid. He's really mean to Mr. McClatchy, his new neighbor, playing small tricks on him like leaning a ladder up against his house and putting trash in his mail box. His dad has little patience with him, since we find out later in the book that Jay's behavior is what caused the family to have to move. Jay is kept on kind of a tight leash, but keeps getting in trouble. He meets Elliot and befriends him, but the two end up in quick sand, barely surviving, especially after they are also attacked my evil birds who carry off Jay's dog, Mr. Phineas, who ends up being returned only to vomit on Mr. McClatchey's porch. It seems like Jay just can't stay out of trouble, and he starts to notice that every time he is doing something he shouldn't, he see lawn gnomes "watching" him. They seem to be all over the neighborhood, and even though they are too heavy for Jay to move, appear in different places all the time. Between the birds and the gnomes, it's hard for Jay and Elliot to stay safe, especially since Jay insists on going out... at night. There is a rather scary, sci-fi twist at the end that I don't want to spoil.