Minor Annoyance
(Illusion)

Range:  5 feet per level
Components:  V, S
Duration:  1 round per level
Casting Time:  1
Area of Effect:  One creature
Saving Throw:  Negates

This spell creates the illusion (in both sound and feel) of a mosquito flying into the victim's ear. The victim will then act appropriately, which usually means stopping and trying to get the illusionary mosquito out of his ear, until either a successful saving throw versus spell is made, or the spell expires.
The spell can be used to interrupt casting of a spell. It will also increase the victim's chance of spell failure by 10% for every round the spell is effective after the first.
The victim gets a saving throw at the time of the casting, and at the end of each round thereafter. For every level the victim is above the caster, it gets a +1 bonus on the saving throw. The illusionary mosquito does not stop the victim from fighting, it does give it a -2 to-hit, however.

