Dorothy, Illustrious Scribe

Whenever you draw a card, you may exile it and put a page counter on it.

You may cast spells with page counters on them from exile. Each creature card with a page counter on it has its mana cost reduced by {4}.

Whenever you cast a creature spell with a page counter on it, it is an Illusion in addition to its other types with haste and "Sacrifice this creature at the beginning of your next end step."