Magic Traps

I'm not sure there's much I can say about magic traps, compared to the physical trap triggers and effects I've been describing for the last couple weeks. It's not that magic traps don't have as much variety as mundane traps (quite the opposite!) But magic traps get their variety from the enchantments used as triggers and trap results; the way a magic trap functions, on the other hand, is pretty simple, as is the way it is detected.

The simplest magic trap is an object created by magic that is dispelled after a set time or when a set condition occurs. For example, a wall or floor created with Phantasmal Forces will vanish when touched by a living being, allowing pit traps covered by false floors, or blinding light sources obscured by false walls. Another example would be a trap door in the ceiling which opens naturally under the force of gravity, but is held shut by a Hold Portal spell; when the spell ends, the door opens, depositing whatever was resting on it down below. An inverse example is a Wizard Locked door that is ajar when found; closing the door for any reason prevents returning down that path. Other magical effects that last longer than traditional spells or which end when specific conditions occur would fit here, too; magical water that raises when anyone not bearing a golden trident enters the room, or a pillar of ice supporting a (physical) lever that lowers when the ice melts (perhaps triggered by bringing any flame larger than a candle within ten feet...)

Next up is an otherwise ordinary trap where the trigger or the link from the trigger to the actual trap is replaced with an intangible, magical connection. Take, for example, a magical floor tile which causes a slab to rotate whenever someone steps on it. The effect of the intangible connection is that it removes pulleys, gears and levers that might otherwise be detectable, plus it can make it difficult to determine what the trigger actually activates. Another for this variant is to limit ordinary traps to highly-specific targets. Physical triggers can be set to trigger under a specific weight, or after a specific delay, or the trigger can be positioned so that it can only be tripped by creatures of a certain height; magical triggers may be "dwarf only" or react to (or be disabled by) a specific password.

Then there are traps with magically-created results. The infamous Magic Mouth is one obvious example, producing sound when a particular event occurs; others may resemble physical effects, but the effect comes from nowhere (traps that throw endless fireballs or lightning bolts, for example, or Exploding Runes.) Many State Effects are produced magically, which is why the previous trap effects post specified Physical State Effects; Magical State Effects, like freeze traps, work differently.

There's also the petty example of an ordinary physical trap with various components made resistant to damage via magic, or which is reset magically.

The main difference between magical traps and physical traps is that the magic removes one or more physical clues, often making the trap much harder to detect. However, magic itself is a detectable feature, via a Detect Magic spell or some other means. We can consider a Mag/S detection method as equivalent to Odor/S, Warm/S, or El/S.