At first, I was like, AWESOME! Seems pretty cool!
And then, I thought, Nymphs... Pulverizer... Eternity... Rustler... uh oh.
As many have elucidated, it would be better if the casting cost was not zero. Generic quanta sounds good to me; however, giving a casting cost as the same element as the creature will help restrain use of SoR in rainbow decks, which may be a good idea.
If it can be coded, I'd like to see that change implemented.
This shard adds a whole new level to the game of surprise and strategy. Good call on making the oft-repeated ability effector card a rare, Zanz.