Mechanic idea - Replicating Storm

Temporary name: Reverberate
Mechanic type: Ability Word 
Mechanic text: "As you cast this spell, for each other spell cast this turn, you may pay its reverberate cost. Then, copy it for each time you paid its reverberate cost. You may choose new targets for the copies "

Knobs:
- Mana value of the original spell (limits how many spells can be cast before)
- Reverberate cost (limits how many copies can be made)
- Making so the card has an extra effect in case it isn't a copy (limits the power of the copy part of the mechanic)

Innovation:
- Tying an escalating additional cost mechanic to a limiter and a escalating trigger mechanic to an additional cost so that each balances the other out.
- Balancing Storm.