Pearl, Blue Handmaiden

As long as you control a blue planeswalker or
another blue legendary creature, Pearl, Blue
Handmaiden has +1/+1 and Hexproof.
{t}: Add {u}. Spend this mana only to cast
planeswalkers or activate costs of creatures. If
you control a blue planeswalker or another
blue legendary creature, add {u}{u} instead.