Text (PC+errata): 0/0. ; You may have ~this~ enter the battlefield as a copy of any creature card in a graveyard. [Oracle 2009/07/08]
The choice is made before it enter play, and it enters play as a copy. This means that any other "As ~this~ comes into play", "This card comes into play with", or "When this comes into play" abilities do apply. [Planar Chaos FAQ 2006/12/13]
You do not have to make a choice, and may actually be unable to if there are no creatures to choose at the appropriate time. [Planar Chaos FAQ 2006/12/13]
