Xenograft | Magic: The Gathering
Formats Xenograft is Legal in
Official Oracle Text for Xenograft
Each creature you control is the chosen type in addition to its other types.
—Jin-Gitaxias, Core Augur
Official Rulings for Xenograft
6/1/2011 : You must choose an existing _Magic_ creature type.
6/1/2011 : Creature cards not on the battlefield and creature spells are not affected.
6/1/2011 : Replacement effects that modify creatures of a certain type as they enter the battlefield will apply (or not apply) before you apply Xenograft's effect. For example, if Warrior is the chosen creature type and you control Bramblewood Paragon, a Runeclaw Bear would not enter the battlefield with an additional +1/+1 counter.