Fire Trap

(Player's Handbook v.3.5, p. 231)

Abjuration [Fire]
Level: Druid 2, Warmage 2, Blighter 2, Sorcerer 4, Wizard 4, Wu Jen 4 (Fire), Sha'ir 4, Greed 4,
Components: V, S, M,
Casting Time: 10 minutes
Range: Touch
Target: Object touched
Duration: Permanent until discharged (D)
Saving Throw: Reflex half; see text
Spell Resistance: Yes

Fire trap creates a fiery explosion when an intruder opens the item that the trap protects.
A fire trap can ward any object that can be opened and closed (book, box, bottle, chest, coffer, coffin, door, drawer, and so forth).
When casting fire trap, you select a point on the object as the spell's center.
When someone other than you opens the object, a fiery explosion fills the area within a 5-foot radius around the spell's center.
The flames deal 1d4 points of fire damage +1 point per caster level (maximum +20).
The item protected by the trap is not harmed by this explosion.
A fire trapped item cannot have a second closure or warding spell placed on it.
A knock spell does not bypass a fire trap.
An unsuccessful dispel magic spell does not detonate the spell.
Underwater, this ward deals half damage and creates a large cloud of steam.
You can use the fire trapped object without discharging it, as can any individual to whom the object was specifically attuned when cast.
Attuning a fire trapped object to an individual usually involves setting a password that you can share with friends.
Note:Magic traps such as fire trap are hard to detect and disable.
A rogue (only) can use the Search skill to find a fire trap and Disable Device to thwart it.
The DC in each case is 25 + spell level (DC 27 for a druid's fire trap or DC 29 for the arcane version).
Material Component: A half-pound of gold dust (cost 25 gp) sprinkled on the warded object.