Dangerous Overclocking

If three or more spells were cast this turn, you
may pay {0} rather than this spell's mana cost.
Flip a coin, if the coin comes heads, target instant
or sorcery spell that cost 3 or less, copy it for
each spell cast this turn. It's controller choose
new targets for the copies. If the coin comes tails, counter that spell and Dangerous Overclocking
deals 2 damage to that spell's controller for each
spell cast this turn.