Ruinous Waterbending
As an additional cost to cast this spell, you may waterbend 
. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for .)
All creatures get -2/-2 until end of turn. If this spell's additional cost was paid, whenever a creature dies this turn, you gain 1 life.
Illustrated by Yuu Fujiki
This printing
Prices
Even if the cost of the spell or ability that waterbend is part of increases or decreases, you still may only tap artifacts or creatures to pay for costs up to the amount of the generic mana in the waterbend cost.
If a waterbend cost is part of the total cost to cast a spell or activate an ability, you may tap an untapped artifact or creature you control rather than pay one generic mana in that total cost any number of times up to a maximum of the amount of generic mana in the waterbend component of that total cost.
"Waterbend [cost]" means "Pay [cost]. For each generic mana in that cost, you may tap an untapped artifact or creature you control rather than pay that mana."
You can tap any untapped creature or artifact you control to pay a waterbend cost, even one you haven't controlled continuously since the beginning of your most recent turn.
If an artifact or creature you control has a mana ability with
in the cost, activating that ability while casting a spell or activating an ability with waterbend will result in the artifact or creature being tapped before you pay the spell's costs. You won't be able to tap it again for waterbend. Similarly, if you sacrifice an artifact or creature to activate a mana ability to pay a cost with waterbend, that artifact or creature won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for waterbend.
