Changing Centaur

Changeling, Convoke (Your creatures can help cast this spell. Each creature tapped while casting this spell pays for {1} or one mana of that creature's color. This card is every creature type at all times.)
When Changing Centaur enters the battlefield, exile all creatures tapped to cast it.
Changing Centaur has the text boxes of all creatures exiled with it in addition to it's own.