Not entirely sure what you mean by yours but heres mine,
Blizzard, lasts whole fight, small chance to stop enemy creature in its tracks. Would work alittle like luck when it happens, creatures turn is skipped. To make it even more interesting creatures like water guardians would be immune to it, but on the other hand the elementals would be 2x more likely to be frozen in tracks. Would require time and elemental principles. Add the 2 skills together and figure out percentage chance from there. 5% chance to happen would be max when both principles are maxed. Meaning it would likely only happen once or 2x per fight much lower then luck effects