Constellation Regulator

Bestow {2}{w}{u}
Enchantments you control have hexproof.
As long as you control ten or more enchantments, play with the top card of your library revealed. You may cast it for {x}, where X
is half of its converted mana cost rounded up.
Spend only white and/or blue mana on X.
Enchanted creature gets +1/+1.