I realize Elfball has not been a deck in forever, but I think this card makes it completely reasonable to think it could happen:

It's tutorable with Chord of calling and Green sun's zenith. It's life loss (not damage). And it has 3 power so it can trade with lodestones and the like. It can be uncounterable via Cavern. It taps for mana with Heritage Druid.
I can easily see situations happening with this card where you are either casting it for 20 damage or able to cast 2-3 of them in a row on the same turn because of the net positive mana you can make in an elf deck. The deck may need to splash Bayou or even Elves of deep shadow to produce the black mana but that seems like a small price to pay.