Retroactive Dispel Magic
(Abjuration, Alteration, Metamagic)

Range:  0
Components:  V, S
Duration:  Instantaneous
Casting Time:  Special
Area of Effect:  Special
Saving Throw:  Special

This spell lets you actually cast dispel magic to counter a spell already thrown at you. If you have memorised the spell, you can cast it at any spell or spell effect thrown that round, even if you have been killed or turned to stone, by the vagaries of initiative and the like. It is assumed that you were casting dispel magic as the other spell was being cast. This spell acts as dispel magic for chance of success based on level.
For example, you have Esmeralda cast polymorph other, which is lots faster than dispel magic. She has initiative all over Glamgon, the PC. He declares that he wants to cast retroactive dispel magic, so effectively as Esmeralda was gathering power for her spell, Glamgon was trying to drain it away. Glamgon had better succeed, lest he truly become a toad (the outcome of the polymorph other, should retroactive dispel magic not succeed).
Note that this spell cannot be cast by a specialised Abjurer or Transmuter, since it also belongs to his opposite school.

