The Bane of Skyward Mills

Voracious (This spell costs {1} less to cast for each creature your opponents control.)
First strike, trample, haste
All green or white creatures able to block The
Bane of Skyward Mills do so.
Whenever a creature dealt damage by The Bane
of Skyward Mills this turn dies, if it had counters
on it, put those counters on The Bane of
Skyward Mills.