Captain Marvel, Existentialist

Indestructible, Hexproof, First Strike, Flying
When you cast Captain Marvel, Existentialist creatures you control gain +X/+X where X is the
highest power among creatures you control.
Whenever Captain Marvel, Existentialist attacks
or becomes the target of a spell double her base
power and toughness until the end of turn.
Creatures you control have "{t}: add {x} mana in
any combination of colors to your mana pool,
where X is the number of creatures you control."