Concealing Stormcloud

As Concealing Stormcloud enters the
battlefield, you may reveal a Giant card from your
hand, Concealing Stormcloud enters the
battlefield tapped unless you revealed a card this
way or you control a Giant.
{1}{u}{r}, {t}: Concleaing Stormcloud deals 3
damage to any target, activate this ability
only if you have cast 3 or more instant and/or
sorcery spells this turn.