Seedbank

Aftershock {x}{g} (You may cast this spell for its aftershock cost with mana produced by lands. If you do, lands that produced that mana become Wastes.)
Seedbank enters play with X charge counters on it
Remove a charge counter from Seedbank: Add one mana of any color to your mana pool.
When Seedbank dies, each Waste you control gains a basic land type of your choice.