Your graveyard-creature will have all the text boxes of all creature cards in it. This means it will have all rules text, flavor text, and watermarks of those creature cards. If a creature card is put into your graveyard, the graveyard-creature will gain its text box. If a creature card leaves your graveyard, that text box will be lost. Phoebe can steal any of these text boxes, but she must do so one at a time.