Every haunted trap has an emanation, which might be as subtle as a drop in temperature or as overt as an object moving of its own accord. A haunted trap’s emanation occurs before the trap takes effect. A character notices the emanation if their passive Wisdom (Perception) score equals or exceeds 10 + the trap’s Haunt Bonus. A character who notices the haunted trap has until the start of their next turn to react, which might include fleeing to avoid the trap or attempting to disarm it (see the following section). Class features and spells, such as Divine Sense and Detect Evil and Good, that discern desecration also detect haunted traps.
Like other traps, haunted traps represent threats leveled toward trespassers. They originate in an area spontaneously, often resulting from overwhelming negative emotions, tragedy, or evil. Just as some terrible fates might cause a tormented individual to rise as an undead creature, so might supernatural evil and violent emotions manifest more generally as one or more haunted traps. Such traps provide a way to theme the dangers and monsters of a haunted place to reveal a grim history or frightening tale. When creating haunted traps, consider what events brought them into being and how the trap’s effects suggest those origins.