Gloom

From publisher blurb: An adventurer delves into a dungeon and enters a room where the light drains away and their torch fades. Blackness stretches on ahead of them like an endless night. Then, suddenly, they feel a pain in their chest. A cold, terrible pain as if something is reaching inside of them and strangling the very beat of their heart. They fall dead to the floor and a specter slides away in silence, satisfied with its latest kill. This creature is a Gloom. An undead spirit of the most lethal variety, its very presence sucks the light away from the area around. Appearing in open daylight as a dome of source-less shadow, the Gloom prefers to stay in dark dungeons or deep forests where it can more easily blend in with its surroundings. Those who let a Gloom get close, court death.