Excerpts From Pearlman's Curiosity by Willie Walsh (1991)
As far as is known, nilbogism affects only goblins, though the variety of effects suggests that other, unrecorded creatures might possibly be carriers of the phenomenon. This isn't to suggest that Nilbogism is a disease; rather it is a magical compulsion that occurs when powerful magic is used too often in one place (such as multiple wishes) and the basic fabric of reality is strained.
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Whatever the individual nuances of a particular case of nilbogism, the phenomenon always follows a basic pattern. Any creature coming within 100 feet of a nilbog is susceptible to acting in a manner contrary to that being's desired intentions. Notable exceptions are creatures with feline blood, from humble house cats to fabulous griffins, all of which seem unaffected by the aura.
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Whether incidental or purposeful, niblogism places persons in real danger of accidental death after a period of 36 hours, as recurring incidents of self-mismanagement increase the odds of death or serious injury.
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Luckily Nilbogism operates only in its 100 foot radiuys sphere of influence, centered on the Nilbog itself...No known substance can block a nilbog's aura, so miners underground could be affected by a Nilbog on the surface, if within range.
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Because of the nilbog's affinity for magic, spells cast within its aura have a special modifier applied to them. Spells that are normally reversible function in opposition to the intention of the spellcaster, unless cast by a device. A priest wishing to cast cure light wounds on a companion will instead cause light wounds.
...Area effect spells, such as fireball are 25% likely to be cast but fizzle out without doing anything; 25% likely to act as close opposites of their type (a fireball might be replaced with ice storm); 25% likely to act as if cast by the Nilbog or a target in the nilbog's aura, at the same level of ability as the caster (the fireball is reflected and explodes in the midst of the adventurers instead of in front of the nilbog; and 25% likely to stick inthe memory of the spell-caster (the spell refuses to be cast for the duration of the caster's stay in the nilbog's range)...
Devices that story spells or are themselves magical in some way are 50% likely to function normally and 50% likely to do the opposite of what they were designed to do.... this applies to cursed items as well...
