|Trigger: Varies||Effects: Multiple Targets, Never Misses|
|Resets: Automatic||Bypass: Avoid|
In some cases there is also an onset delay. This means these traps can be triggered and the effect happen in a certain amount of time (sprinklers in a room) or a delay before the substance affects the characters (such as a room filling with water.
Examples of the things that might be vented or sprayed included slime, shrapnel, cold, acid, boiling water, flaming oil/tar, sewage, mummy dust, poison, fire, magma, smoke, methane, sand, steam, sulphur, and water.
If a to hit roll is required it will always ignore armor, but not necessarily shield bonuses. Saving throws may apply given the circumstance. Rods, Staves and Wands is the traditional saving throw for such attacks, allowing half damage or to avoid instant death.
Detection: These traps can be both the best kinds of traps, and the worst kinds of traps. Because they often have extremely negative properties, they can be ran in such a way where they are just Gotcha! traps, causing death or massive damage very quickly. However, this is an extremely poor way to run such traps, for several reasons. None of the vents and sprays above will be able to remove signs of their presence. Some examples
- Slime will leave a slick slimy coating on the walls and floor
- Shrapnel will leave gouges and scars in the walls and floor and ceilings
- Cold vents and sprays may show some signs of their presence due to temperature differences, areas where the cold strikes repeated may show cracking, the growth of natural molds and fungi may be retarded. If the trap is triggered often or recently, there may be frost, ice or water on surfaces. If it has been triggered somewhat recently, the water will affect the appearance of the walls (they will be cleaner).
- Acid will leave pits and scarring on whatever surface it is sprayed on. There may be a scent, or the players eyes may start to become irritated.
- Boiling water may show up due to temperature differences, and will generally insure a sparkling clean area where the walls and floor are blasted with it.
- Flaming oil and tar will generally cover the upper walls and ceiling with black soot, and the floor may appear greasy or covered in scorch marks. Tar will stick to a surface and blacken and harden under high heat. The hallway may carry a scent of burning tar.
- Sewage will smell overpoweringly terrible, unless it is stored behind water (like in a toilet) or behind an air tight valve or door. There will still be an odor because it will be triggered occasionally filling an area with filth. There may be an unusually high amount of mold or spores or other type things in the area due to the rich food source the filth provides.
- Mummy Dust may leave a coating of dust on surfaces, cause a musty spell, and their may be corpses in the hallway.
- If a poison is being used in a spray, it most likely is fairly virulent, and therefore their should be corpses, either dessicated in a forgotten dungeon like a tomb, or bones or signs of being dragged off in a more active area.
- If fire is being vented out, then on the surface that the fire is across from there will certainly be burn or scorch marks. Their may also be burnt corpses.
- Magma if sprayed or vented out, will melt and re-solidify, causing whatever surface the magma contacts to deform. Areas where magma is sprayed will bubble, twist, buckle, and bulge from the constant melting and re-hardening. Bones and various other mineral items (armor and such) may be embedded in seeming solid surfaces.
- Smoke will often linger for far longer then it takes to dissipate, leaving a smell for 60' to 100' from the location of the trap for days.
- Methane is a very dangerous trap, relying on the players flaming light to trigger an explosion. There are several things to keep in mind with methane. First, it is odorless, the natural gas smell you are familiar with is a modern additive to help detect leaks. Second, it displaces oxygen, so even if the entire party has some means of seeing in the dark, it can rapidly cause asphyxiation. Use the rules for how long characters can hold their breaths unprepared for the length of time they can stay conscious.
- Sand will both collect on the floor (and in clothes, armor, food, despite the best intentions). The first notice the adventurers will have will likely be the sound of sand crunching under their feet. Any surfaces subject to a spray of sand will likely be scrubbed clean. Repeated sand blastings will scour a surface clean, but will also remove the top layer, exposing rougher rock or metal beneath. Sometimes this will be used to fill a sealed chamber, in which case sand coated corpses will often be discovered.
- Steam is going to insure that whatever surfaces the steam hits are clean, except for the bits of boiled flesh that it removes from it's targets. Do not forget to continue to apply damage as heat metal for people caught in steam wearing metal armor.
- Sulfur is an interesting compound, either acidic causing burns, or a fine dust causing explosions, or a gas, causing choking and irritation. It is also known as brimstone. The primary method of detection is it's overpowering rotten eggs smell, which is natural.
- Water is often not sprayed on people for damage, but more often is used to fill a sealed chamber trapping and drowning whoever is within. Water traps often leave water marks, as the fluid removes dirt and grime from surfaces and deposits it on a line along the wall. It also can have a briny or salty smell.