SPELL-PRISMATIC-SHIELD

The Prismatic Shield spell creates a shield of quasi-real illusionary colors around the character's body. Whenever a melee opponent strikes the character, the attacker will be struck by one of the colors in the shield. Each color has a different effect upon the attacker, though the more powerful effects can only be triggered by stronger attacks.

Red   - casts faerie fire, curse, or does minor damage
Orange- saps vitality
Yellow- drains mana
Green - does color-based damage
Blue  - casts blindness, or does damage
Violet- casts dispel magic

(Mobiles take damage instead of losing mana or vitality.)

The shield also confers a 10% resistance against color-based damage.