Blasting Wand

Armed creature gets two AP counters as long
it is armed with this card.
Arm {0} (You may cast this card from your sideboard. {0}: Attach to target legendary creature
you control as a sorcery. When a legendary creature you control enters the battlefield, you may
arm that creature as an instant. As long as this ability is on the stack, your opponent can't cast spells or activate abilities.)