Hazardous Dice

At the beginning of each end step, put a luck counter on Hazardous Dice.
Once per turn, each player may roll a number of six-sided die equal to the number of luck counters on Hazardous Dice, then that player may cast a spell from their hand without paying it's mana cost if it's converted mana cost is equal to the result of one of those die. If they can't, Hazardous Dice deals X damage to that player equal to twice the number of luck counters on it.
"But I had a system!"