Living Plane

• WWizards of the Coast2008-10-01
  Official Ruling
  This has the supertype world. When a world permanent enters, any world permanents that were already on the battlefield are put into their owners' graveyards. This is a state-based action called the "world rule." The new world permanent stays on the battlefield. If two world permanents enter at the same time, they're both put into their owners' graveyards.
• WWizards of the Coast2009-10-01
  Official Ruling
  A noncreature permanent that turns into a creature is subject to the "summoning sickness" rule: It can only attack, and its abilities can only be activated, if its controller has continuously controlled that permanent since the beginning of their most recent turn.

Rulings via Scryfall