A polymerized spell is two spells occupying the same slot. The polymerized spell's final level is equal to the sum of the component spell levels plus three.
When you cast a polymerized spell, roll a percentile.
01-10 - resolve the effects of the lower level spell only. If same level, DM choice.
11-20 - resolve the higher level spell only. If same level, your choice.
21-70 - resolve both spells. Pick the same targets and areas when applicable.
71-100 - the effects of the spells combine with unpredictable(gm fiat) results. The resulting spell is almost always more powerful than the sum of its parts.
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What do you guys think? I was thinking of what would happen if you combined color spray and diamond spray, and came up with this idea because of it.
Bump for homebrew interest. Does anyone think this is overpowered, seeing as it has a 50% chance to be a bit more powerful than quicken metamagic, and uses fewer slots?
I would recommend that you drop the percentile and then it would be a good alternative to quicken. Otherwise, it would rarely be better than quicken and far more often be way worse.
If you don't have the percentile, then it's only marginally better than quicken if you use 2 1st level spells. With 2 spells of 2+, I would say that this is kinda worse. The only advantage being that you could get off 3 spells with this and a quickened spell.
What if I dropped the 1-20 portion, or dropped the level adjustment to total+2, or both?
Changing the level adjustment to total+2 might work. The only case that I don't know about is if this is used with 2 lvl 1 spells. The question there is "is casting 2 lvl 1 spells as a 4th level spell broken?" If you think the answer is yes, then give it a minimum adjusted level of 5
The other problem I just realized about this feat, is that you can't put it into a Rod. But that doesn't mean this can't be a metamagic feat.