Finders Keepers: Ring of Untrained Magic

The following text & stats are designated Open Gaming Content as per the OGL:

Ring of Untrained Magic: This powerful items allows the wearer to cast a single magic-user spell of any level once per day. Note however that there is always a base 5% chance of any spell cast from the ring going awry, modified by the variables on the following chart:

Intelligence 4 or Less: Unusable

Intelligence 5-6: +45%

Intelligence 7-8: +25%

Intelligence 9-13: +10%

Each Point of Intelligence Over 12: -1%

Each Magic-user Level: -2%

Illusionist: -1%

Cleric or Druid: -1%

Fighter: +15%

Thief: +10%

Spell Being Cast is 1^st Level: +0%

Spell Being Cast is 2^nd Level: +5%

Spell Being Cast is 3^rd Level: +10%

Spell Being Cast is 4^th Level: +15%

Spell Being Cast is 5^th Level: +20%

Spell Being Cast is 6^th Level: +25%

Spell Being Cast is 7^th Level: +30%

Spell Being Cast is 8^th Level: +35%

Spell Being Cast is 9^th Level: +40%

Note that regardless of the variables, the base chance for a casting to go awry will never fall below 5%.

If a spell cast from the ring does go awry, then there are several possible outcomes: the spell might fail completely, in which case the ring cannot be used again for another week; the spell may be miscast, resulting in the opposite effect occurring other than the one desired by the wearer, if the spell is reversible or can have an opposite effect; spells with detrimental effects can harm the wearer of the ring, rather than the intended target or victim of the spell; a portal or gate opens up, forcing the ring wearer into another dimension or plane randomly determined by the Referee; a strange effect as dictated by the Referee can result, rather than the desired effect of the ring wearer.