Traps should be used sparingly, lest they lose their charm. A hidden pit can be a fun surprise, but too many traps in an adventure can lead players to become overly cautious, which slows down the game.
The best traps are fleeting distractions that skilled characters can overcome in a short amount of time or deadly puzzles that require quick thinking and teamwork to overcome. Traps that are undetectable and inescapable are rarely fun.
The description of a trap includes the following parts after the trap’s name:
Severity and Levels. A trap is designated as a nuisance or as deadly for characters of certain levels. A nuisance trap is unlikely to seriously harm characters of the indicated levels, whereas a deadly trap can grievously damage characters of the indicated levels.
Trigger. Traps are often set to go off when a creature enters an area or touches an object. Examples of triggers include stepping on a pressure plate, crossing a trip wire, turning a doorknob, or using the wrong key in a lock.
Duration. Some traps have durations expressed in rounds, minutes, or hours. Others specify that their effects last until the trap is destroyed or dispelled. If a trap’s duration is instantaneous, its effect is resolved instantly. If a trap resets after activating, that fact is noted in this entry. A trap is otherwise inert after activation.
Use caution when introducing a trap to characters of a level lower than the trap’s level range. A trap that is a nuisance at one level range could be deadly to characters of a lower level range.
When designing your own traps, use the Building a Trap table to determine an appropriate total amount of damage for the trap to deal based on its level and severity. If the trap also applies a condition, consider reducing the damage.
If the trap requires an attack roll or allows a saving throw, use the appropriate columns on the table to determine the attack bonus or an appropriate save DC.