One use only. When an enemy spell has been cast, a Wizard who has a Hex Scroll can read it instead of attempting to dispel the spell. The spell is cast as normal, but a portion of the spell's energy is transformed and redirected at the caster. The enemy wizard can resist the spell's effects by rolling equal to or under his wizard level on a D6. If he fails, an amphibian transformation takes hold and he becomes a small, slimy toad!
Whilst transformed, the wizard cannot channel or cast spells, all of his magic items and mundane equipment (armour, weapons, etc.) temporarily stop working and all of his characteristics are reduced to 1 (except for his wounds, which are unaffected). His controlling player can roll a D6 at the start of each of his subsequent magic phases; the spell dissipates on a roll of 4+ and the wizard returns to his normal form (but still attempts to eat flies for several days afterward).