Welcome to Camp Nightmare, Paperback/R. L. Stine

It's the little camp of horrorsNow with bonus materials Next summer you'll stay home...if you survive The food isn't great. The counselors are a little strange. And the camp director seems demented. Billy can handle all that. But then strange things start to happen after dark, his parents won't answer his letters, and his fellow campers start to disappear. What's going on? Camp Nightmoon is turning into Camp NightmareAnd Billy might be next.