Stephen King's The Mist Wiki has a more comprehensive article on the same creature. For it, see Gray Widower at The Mist Wiki
Black spider-like predators from another dimension (possibly Todash space), each about the size of a dog which hunt by scent. These have the ability to project acidic "spider-webs" which can burn through materials like cloth and flesh. They claim the lives of Jim Grondin, Buddy Eagleton, Dan Miller, Mike Hatlen, Hattie Turman and several patrons of the next-door pharmacy.