This opens up a HUGE amount of possibility, especially depending on how the GM approaches the use of magic in his/her campaign. Is magic like ‘technology’ and more of a tool, rather than a force to be reckoned with? Is magic a wild and unnatural thing, and the possibility of a fumble could be an Ultimate Bad Thing and a critical hit an Ultimate Yesss-I-Feel-The-Power! moment?
I did a quick search on Google (fumble spell chart) and found [url=http://www.nihsen.com/Ironwood/Fumble_Chart.doc]this interesting set of weapon/magic fumble/critical charts[/url] (Microsoft Word Document) by David Nihsen. I’ve copied them locally, in case his server or this link ever dies, but in case I want to indulge the Great RNG in its Divine Randomness, these charts are very thought provoking! Not all of the mechanics are quickly translated to m20/74, but they give a lot of options towards your own fumble ideas.
91-98 Magic shoots out of caster’s nose like a sneeze. Caster loses nose. CHR is at 10%.