Flamme's Hindsight:

If successful, reroll a failed check involving a d20; this may be done after the roll is made. If the original roll was a natural one, double the initial cost. If cast by nation magic, suffer -1 temporary karma for every 1 the caster misses the re-rolled check's DC, in either directions. If cast by character magic, caster suffers a 10% chance to suffer a magical malfunction for every 1 the caster misses the re-rolled check's DC, in either directions; this may result in multiple malfunctions. If the above downsides are mitigated in any sense, increase the base cost and complexity by 2. A single roll can only gain the benefits of a Hindsight spell once.