Complex sentence: Roulette's mutant power is to generate disks of psychic energy that alter the laws of chance of anything they touch, resulting in either good or bad luck for their subjects by altering the probabilities field around the victim at whom she throws the disc.
Split into simpler sentences: Roulette's mutant power is to generate disks of psychic energy that alter the laws of chance of anything they touch, resulting in either good or bad luck for their subjects. Roulette can create discs of psionic energy which alter the probabilities field around the victim at whom she throws the disc.