My Best Friend is Invisible
The invisible boy who attacks the car in the trailer for Goosebumps could potentially be a character from "Let's Get Invisible", but seems more likely to be poor, lonely Brent Green from "My Best Friend is Invisible". This book ends with one of Goosebumps' better twists, which we won't spoil, but if the invisible boy in the movie is Brent then he could end up causing a whole lot of trouble... whether he means to or not.
Return of the Mummy
The woman dressed in Ancient Egyptian clothing featured in one of the stills from Goosebumps is probably Nila, from the sequel book "Return of the Mummy". Nila is thousands of years old and attempts to bring her mummified brother, Prince Khor-Ru, back to life so that the two of them can rule over Egypt once more.
Revenge of the Lawn Gnomes
This guys might be small and ugly, but they can also be pretty dangerous in large numbers. In the book they engage in all kinds of lawn-unfriendly activities like crushing plants and vegetables, and in the movie they form part of the main infantry in Slappy's monster army. They can seen at several points in the trailer, which ends with one of the poor little guys getting smashed with a frying pan.
The Scarecrow Walks at Midnight
If Jeepers Creepers wasn't enough of a warning to stay away from creepy-looking scarecrows, then Goosebumps might just do it. The walking scarecrow was featured at last year's Comic-Con presentation and can also be spotted in the group shot of the new trailer.
Stay Out of the Basement
Another story that's popular largely by virtue of being one of the very first Goosebumps books ever published, "Stay Out of the Basement" is about a man whose strange horticultural experiments lead to the creation of a plant clone that ends up stealing his identity. In the movie, the monster army includes some dangerous-looking plants that resemble the ones in the book.