Felidar Guardian

• WWizards of the Coast2017-02-09
  Official Ruling
  If a creature token is exiled this way, it will cease to exist and will not return to the battlefield.
• WWizards of the Coast2017-02-09
  Official Ruling
  After the permanent returns to the battlefield, it will be a new object with no connection to the permanent that was exiled. It won’t have any additional abilities it may have had when it was exiled. Any +1/+1 counters on it or Auras attached to it are removed, and any Equipment will no longer be attached.

Rulings via Scryfall

• WO
  Wizards of the Coast2018-05-10

  Felidar Guardian was unbanned in brawl on May 10, 2018. Because of its singleton nature, we believe these cards will be less problematic in the Brawl environment. Ultimately, with access to a maximum of one copy of each card and only when using specific commanders, we predict that overall Felidar Guardian will add more fun and variety to the format through its other interactions than the Felidar Guardian–Saheeli Rai combo subtracts. Source: https://magic.wizards.com/en/news/news/future-brawl-2018-05-10
• WO
  Wizards of the Coast2019-11-04 · edited

  Felidar Guardian was banned in pioneer on November 4, 2019. The Felidar Guardian/Saheeli Rai combination threatens metagame diversity by requiring decks to present specific types of early interaction while developing their own strategy or else immediately lose the game. Rather than allow this combination to warp deck building and the metagame around it, we're choosing to ban a card. Of the two options, Felidar Guardian is the most likely to break again with existing or future cards. Source: https://magic.wizards.com/en/news/news/november-4-2019-pioneer-banned-announcement
• WO
  Wizards of the Coast2017-04-27

  Felidar Guardian was banned in standard on April 27, 2017. Saheeli-Felidar's win-loss ratio and metagame share has actually increased since the release of Amonkhet, making up approximately 40% of 5-0 and 4-1 decklists in Magic Online Standard Leagues. We believe this banning will be a significant step toward making Standard the fun, dynamic format we all want it to be. Source: https://magic.wizards.com/en/news/news/addendum-april-24-2017-banned-and-restricted-announcement-2017-04-26