you can use this post to discuss the Comet Storm card from worldwake:
Comet Storm
XRR
instant
Mythic Rare
Multikicker 1 (You may pay an additional 1 any number of times as you cast this spell)
Choose target creature or player, then choose another target creature or player for each time Comet Storm was kicked. Comet Storm then deals X damage to each of them.