Add a new subrule to rule 2.8 (“Spells”), titled “Potion of Fast Learning and Temporary Haunting”, with the text:

Difficulty level: ALC (-3)
Effect: If the Targeted Student is not the Caster and doesn’t join, this spell does nothing.
If the Targeted Student was in a class that has not ended when the spell is cast, that class counts as having ended for that student. The student cannot be the target of Disruptions for that class and is not affected by the Disasters triggered in that class.
If the caster has an ALC of D, E, F or Ungraded when the spell resolves (but before decrementing ALC as part of the cost for casting the spell), the caster must roll a DICE2 in the GNDT before the effect is applied. On a 1, the Targeted Student’s Condition becomes Ghost. Other effects work as normal.