Belbe, Ever-Changing

Mutate {3}{w}{u}{b}{r}{g}
Creatures you control have: "This creature gets
+X/+Y, where X is equal to the combined power
of all mutated creatures under this creature and Y
is equal to the combined toughness of all mutated
creatures under this creature."
As long as you cast this card for its mutate cost,
you may ignore commander tax.