Tenser’s Transformation

Tenser's Transformation is a sight guaranteed to astound any creature not aware of its power, for when the magic-user casts the dweomer, he or she undergoes a startling transformation. 

The size and strength of the magic-user increase to heroic proportions, so he or she becomes a formidable fighting machine, for the spell causes the caster to become a berserk fighter! The magic-user's hit points double, and all damage he or she sustains comes first from the magical points gained; so if damage does not exceed original hit points, none is actually taken, but if damage beyond the additional amount is sustained, each point counts as 2 (double damage). 

The armor class of the magic-user is a full 4 factors better than that he or she possessed prior to casting the spell (AC 10 goes to 6, AC 9 to 5, AC 8 to 4, etc.), all attacks are at a level equal to those of a fighter of the same level as the magic-user (i.e., the spell caster uses the combat table normally restricted to fighters), and although he or she can employ a dagger only in attacking, damage inflicted by the weapon is at +2 additional hit points, and 2 such attacks per round are made by the magic-user. 

However, it is worth noting that this spell must run its full course, and the magic-user will continue attacking until all opponents are siain, he or she is killed, the magic is dispelled, or the Transformation duration expires. 

The material component for casting this dweomer is a potion of heroism (or super-heroism) which the magic-user must consume during the course of uttering the spell.