Circle of Burning

Circle of Burning comes into play face down
as a colorless enchantment with no mana cost.
Turn it face up at any time by paying its
activation cost.
Activate {3}
When Circle of Burning is turned face up,
sacrifice it and until end of turn whenever a
creature deals damage to you, that creature gets
a burn counter that has, at the beginning of your
upkeep this creature deals damage equal to the
number of burn counters on it to its controller.