The Creatures from Beyond Beyond by R.L. Stine
Randi and her twin brother, Tyler, didn't think it was such a great idea for their family to spend the summer in a vacant house in a small town called Blairingville. Boringville seemed more like it. But as it turns out, the vacation was anything but boring! There's a surprise in every closet here-and not the good kind. Alien creatures are lurking, mysterious dolls are growing, and there's a sinister twelve-year-old boy with a powerful hypnotic pendant who may hold the key to the entire mystery. Now if Randi can just escape a monster's clutches, send some space visitors back to who knows where, and regain control of her free will, she might just get her family back home in one piece. It's another scary good read from the master of shriek-out-loud horror, R.L. Stine.