False Trap

By means of this spell, the mage weaves an illusion around an object, making it appear trapped to any normal inspection (such as by a thief). Any such examiner has an 80% chance of finding and believing the [false trap]. This likelihood decreases by 3% per level of experience of the thief. Furthermore, if a thief attempts to remove the illusory trap, believing it to be real, there is only a 20% likelihood that the illusion will be dispelled or exposed by these efforts. In this case, the thief, seeing the illusion unchanged, will usually conclude that the attempt to remove the “trap” has failed. Only one [false trap] may be placed within a 50 ft radius, and if two items bearing this illusion come within 50 ft of each other, both will be dispelled.