Fear the Barfitron (Monster Juice Series #1)

When Chris Taylor discovers that the residents of the retirement home where he volunteers are secretly monsters--and have stolen what appears to be his life essence--he leaves to recruit his friends to help him get it back. But once they return to the retirement home, the boys find themselves at the center of a vomit-inducing war against some of the grossest monsters this world has ever encountered. Will Chris and his friends join the residents to fight off the Barfitron?