The subject becomes blinded or deafened, as the character chooses. In addition to the obvious effects, a blinded creature suffers a 50% miss chance in combat (all opponents have full concealment), loses any Dexterity bonus to AC, grants a +2 bonus to attackers' attack rolls (they are effectively invisible), moves at half speed, and suffers a -4 penalty on most Strength- and Dexterity-based skills. A deafened character, in addition to the obvious effects, automatically fails Listen checks, suffers a -4 penalty on initiative and has a 20% chance to miscast and lose any spell with a verbal (V) component that he tries to cast.