Aegwynn, Creator of Karazhan

Changeling (This card is every creature type.)

As Morophon, the Boundless enters, choose a
creature type.

Spells of the chosen type you cast cost {w}{u}{b}{r}{g}
less to cast. This effect reduces only the amount of
colored mana you pay.

Other creatures you control of the chosen type
get +1/+1.