I voiced my wish to see some chance of spell failure in D&D in my recent post about Fantasy Magic. Having been called out by Bonemaster I have put together my suggestions as to how to use spell failure.
My plan is not to make it a frequent or lethal event, just a way of adding some variety and encouraging some care and thought from wizards. These ideas are based on my theory about the origins of magic.
First, each spell cast requires a “notional” concentration check. This is to ensure the caster does not forget an element of the ritual or fluff it. A roll of 1 denotes a mistake and potential spell failure.
Roll again and add the spell level (bigger spells need more raw magic and hence increase the result of failure). Compare the result to the outcomes below.
| 0-20 | The spell fails and is lost. |
| 21 | As above but also lose another random spell (contamination during preparation). |
| 22 | Random spell outcome of the same school and level. |
| 23-24 | Random spell outcome, opposite school, same level. |
| 25-26 | Random spell outcome, same school but random level. |
| 27-28 | Random spell outcome of the opposite school but random level. |
| 29 | Random target, same spell. |
| 30 | Target self, oposite school and random level. |
As you can guess, the chance of failure is small and the outcome rarely fatal. Casting level is not an issue as we can all make mistakes. Finally I am assuming the GM will determine the random outcomes. Please give them a try if you are interested or better still, post your ideas and opinions.