In the Mouth of Madness (1994)

With the disappearance of hack horror writer Sutter Cane, all Hell is breaking loose...literally! Author Cane, it seems, has a knack for description that really brings his evil creepy-crawlies to life. Insurance investigator John Trent is sent to investigate Cane's mysterious vanishing act and ends up in the sleepy little East Coast town of Hobb's End. The fact that this town exists as a figment of Cane's twisted imagination is only the beginning of Trent's problems.