Criellan, Blade of Mystic Doom

You have Hexproof.
Equip {x}, where X is that creature's power.
Equipped creature gets +7/+7 and gains Lifelink,
Double Strike, Hexproof, Flying, Trample, and Vigilance.
{t}: Add {p/w} to your mana pool. ({p/w} can only be
paid by tapping this artifact.)
{t}: Criellan, Blade of Mystic Doom deals damage
to target creature, player, or planeswalker equal to
equipped creature's power.