If Phyrexian Metamorph somehow enters at the same time as another permanent (due to Mass Polymorph or Liliana Vess's third ability, for example), Phyrexian Metamorph can't become a copy of that permanent. You may choose only a permanent that's already on the battlefield.
Phyrexian Metamorph
If the chosen creature is copying something else (for example, if the chosen creature is a Clone), then your Phyrexian Metamorph enters as whatever the chosen creature copied, except it's also an artifact.
You can choose not to copy anything. In that case, Phyrexian Metamorph simply enters as a 0/0 artifact creature and is put into its owner's graveyard as a state-based action (unless something else is raising its toughness).
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Jung Park
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
