Deafness effect

Deafness is a status effect introduced with the original edition of Baldur's Gate II. It shuts down a victim's hearing, which most notably causes a 50% chance of casting failure for both arcane and divine magic, but leaves usage of innate abilities unaffected.
Like many other Baldur's Gate II mechanics, this effect has been ported back into the first opus of the series through Beamdog's Enhanced Editions.
==Gameplay==
*A deafened character cannot benefit from an allied Bard's song.
*Inflicting multiple Deafness effects on a single target will not further reduce their odds to cast successfully, but one Deafness effect can be combined additively with multiple Casting failure effects as found in spells such as Miscast Magic. For example, with Deafness, a Casting failure effect of 30% and another of 10%, total odds of failure would be 90%. Unfortunately, enemy AI sometimes casts spells in ways that ignore casting failure, interruption or Silence.
*Almost no enemy in the series is explicitly immune to Deafness as a status effect. Mordenkainen's Sword summons and some beetles and fungi from Siege of Dragonspear are the only ones, together with Aawill who wears the Bard Hat if the player imported it to Baldur's Gate II: Enhanced Edition from Siege of Dragonspear.
*As with all status effects, configuration details vary depending on the attack trying to cause Deafness. For example the Deafness spell sets Deafness to be permanent until death or cure, Holy Word allows no saving throw to resist the status ailment, and Collar Bell bypasses almost all defenses when the saving throw is failed.