I want a Backpack Trap!

[Ninjaxenomorph]

There has been a rash of thieving in our party (and it is definitely not the Drow Arcane Trickster), and I want to not only protect my gold, but also set some sort of example. I was inspired by Alaeron in City Of The Fallen Sky.

I just bought myself a Handy Haversack, and I was planning on stowing the wealth (condensed via platinum, gems and other stuff) in one of the side pockets. To protect this, I want to have some sort of magic device trap hooked up to a wand of Corrosive Touch. I can't find the rules for the cost of building or buying such a trap, but my GM tells me that it will cost a bit more due to the difficulty of building a trap inside a bag, like building a ship in a bottle, in addition to taking up space.

[Darksol the Painbringer]

I believe there is a cursed item that works like how you describe, though it's not friendly to anyone. I'd talk to your GM (or if you are the GM, brainstorm ideas) about how to make the concept come to life.

One idea that comes to mind is to add a permanent "Create Pit" and "Plane Shift" spell effect to that pocket (incurring price adjustments as normal) to simulate them being stuck in a dimensional hole.

[Ninjaxenomorph]

Planar spells are... Complicated, in this setting, to say the least. I know my idea works, and is completely legal, but I don't know how to price traps.

[Darksol the Painbringer]

Ninjaxenomorph wrote:

Planar spells are... Complicated, in this setting, to say the least.

I re-read your post; thought you wanted the trap to suck them in and leave them hanging until you decide to pull them out. Sorry for the misunderstanding.

Honestly, the rules for making traps can be difficult, since a simple Fireball trap is thousands of gold. Yours would be a simple fix, since Craft (Trap) to have a proxy go off would be simple, but this raises question to opposed perception DCs and save DCs, which only complicates things.

If you're worried about people getting into your haversack, it actually has a safety feature; only the bearer can reach into and acquire things from its pockets. If you want to have it protected further, having a secret chest spell helps in hiding it.

[Ninjaxenomorph]

Only the wearer can choose the item that appears, others can root around in it. The problem here is not safety, its catching the thief red-handed. Or in this case, melts-handed.

[HNNNNNNG]

Maybe something like this?

Backpack Pocket Trap CR 5
Type magic; Perception DC 25; Disable Device DC 20
Effects
Trigger touch; Reset automatic
Effect spell effect (Corrosive Touch, +15 touch attack; 3d4 acid)

Cost: 1650gp, Craft DC 20

How I built it. Followed the trap information in the book, hope everything's right.

Spoiler:

DC 25 to notice (cr 1)
Disable device DC 20
Effect: +15 touch attack (cr1)
damage: corrosive touch (3d4 acid) (cr1 dmg, +1 for spell)
Automatic reset (1500gp, cr1)
cost (spell) 150gp

CR 5, craft dc: 20

[Ninjaxenomorph]

I want it triggered from a level 1 wand, that way it is only a slap on the wrist and it resets. Spell traps don't reset, but Magic Item ones do. Another big thing is being able to bypass it myself.

[tonyz]

You could just settle for detection -- have someone cast a magic mouth on the haversack that yells "Thief!" if anyone but you takes stuff out of it. Simpler than trying to damage them and hoping they don't use healing magic before you notice that the ex-paladin has acid scars on his hands.

[Unruly]

I know it isn't what you asked, and it's really just a more expensive version of Magic Mouth, but there's also a permanent Alarm spell. Set it to a mental alarm and you can catch them in the act if they don't say the password before so much as touching the pack.

[Ninjaxenomorph]

Figured out the trap is 2250 for an automatic reset trap with a wand of Corrosive Touch.

[Kimera757]

I was just going to suggest Glyph of Warding (the type that makes a loud bang), as catching the thief is probably more important than killing them.