A death trap is a room or other feature in an adventure that immediately kills the adventurer when they enter it or use it. Some authors give the player warnings or clues that going a certain way may be fatal; others give little or no indication of danger and allow the adventurer to walk unknowingly to their doom. Deadly traps that occur with little warning tend to be unpopular with players and reviewers.
One of the earliest room-based death traps occurs in The Cave of the Mind when the adventurer encounters a door marked "do not enter". If the adventurer steps through, they fall down an open elevator shaft and are killed.