This spell brings the caster into an immediate mental contest, a direct battle of mental powers against another spellcaster. If the spell is successfully cast, the target must enter the duel. If the Mental Duel is mistakenly initiated with a non-spellcaster, the caster's MPs are expended but the spell has no effect.
On the first round of the mental duel, each spellcaster rolls D6 and adds their magic level. If the caster's total score is higher than that of their enemy, the enemy loses 3 MPs; if lower or equal, the caster loses 3 MPs. On subsequent rounds, each spellcaster can attempt to break off the duel by making a successful magic test, should they so wish. If neither side does so, or the roll is failed, the round continues as described above.
This spell is dangerous, for once a Mental Duel is begun, neither combatant may stop until one or other is reduced to zero MPs (or below), or until one caster wishing to evade the duel makes a successful magic test. No other spells may be cast during a Mental Duel and no combat actions or movement are possible. The duellists are totally absorbed in their duel and oblivious to other happenings. However, a duellist struck by a melee opponent is allowed a magic test to escape the Mental Duel - this may permit them two such tests in one round if the caster is already trying to evade the duel.
A caster reduced to less than zero MPs by this spell will fall unconscious for 2D10 hours, gain 1 Insanity Point, and must make a magic test or have their Power Level permanently reduced by 3 points.