Limited Wish
Limited wish is a powerful spell, allowing the caster to reshape reality in accordance with his or her desire, but only to a limited degree. The spell may be used to grant minor wishes (undoing curses, granting small quantities of gold, duplicating the effects of lower level spells, etc.) The effects of the spell will be permanent for most minor requests, particularly when used to duplicate a lower-level spell that has a permanent or instantaneous duration.
However, a limited wish is not powerful enough to make major changes in reality. It cannot bring the dead back to life, grant a level, or permanently change ability scores. In many cases, the GM will be called upon to determine whether the caster’s wish is within the power of a limited wish spell or whether the results of the request will suffer from flaws due to the spell’s limitations. Flaws would include limited durations or partial results. The guidelines set forth above should give the GM some assistance in making such determinations.
In the case of unreasonable wishes, the GM may decide to follow the wording of the spell precisely but pervert the intent, limit the duration of the spell to a very limited time (perhaps mere seconds!) or simply rule that the whole spell fails.
The guideline here is that wishes are granted by someone or something, which may or may not be kindly disposed to the player characters. The more greedy or selfish a wish, the greater the chance that a mischievous or actually evil power will take the opportunity to teach this upstart mortal a lesson.