It blinds and deafens undeads. Maybe by design (becuase it's rare), maybe not?

<indoor civilized>
Williad's fireball MASSACRES him!
Your ears ring and your eyes burn as a bubbling flask explodes into a ball of searing flame!
Your fireball does UNSPEAKABLE things to you!

You are affected by:
Spell: 'detect invis' for 54 hours.
Spell: 'greater undead' for 30 hours.
Commune: 'bless' modifies save vs spell by -14 for 26 hours.
Commune: 'bless' modifies hit roll by 7 for 26 hours.
Spell: 'detect magic' for 22 hours.
Power: 'nightwalker' for 12 hours.
Spell: 'lesser golem' for 9 hours.
Spell: 'resist breath' modifies save vs breath by -10 for 8 hours.
Spell: 'armor of living bone' modifies armor class by -20 for 6 hours.
Spell: 'wraithform' for 4 hours.
Spell: 'wraithform' modifies pierce resistance by 38 for 4 hours.
Spell: 'wraithform' modifies slash resistance by 38 for 4 hours.
Spell: 'wraithform' modifies bash resistance by 38 for 4 hours.
Spell: 'wraithform' for 4 hours.
Spell: 'barrier' modifies armor class by -80 for 4 hours.
Skill: 'deafen' for 2 hours.
Skill: 'blindness' modifies hit roll by -5 for 2 hours.
Skill: 'divination' for 2 hours.

It'll feel a tad different for undead now.