For more than 30 years, author R.L. Stine’s spooky series “Goosebumps” has been scaring kids in print, and now on the screen. “This Halloween, thousands of kids will go out as Slappy the dummy. And it’s a thrill, really,” Stine said. The best-selling children’s book author still writes every single day, pecking away with just one finger, from his Upper West Side apartment.