Rampaging Ferocidon

• WOTC Official Reminder Textofficial rules
  Menace — This creature can't be blocked except by two or more creatures.

• WWizards of the Coast2017-09-29
  Official Ruling
  Rampaging Ferocidon's last ability triggers whenever any player has a creature enter the battlefield, including you.
• WWizards of the Coast2017-09-29
  Official Ruling
  If an effect says to set a player's life total to a number that's higher than the player's current life total while Rampaging Ferocidon is on the battlefield, the player's life total doesn't change.
• WWizards of the Coast2017-09-29
  Official Ruling
  Spells and abilities that cause players to gain life still resolve while Rampaging Ferocidon is on the battlefield. No player will gain life, but any other effects of that spell or ability will happen.
• WWizards of the Coast2017-09-29
  Official Ruling
  If another creature enters the battlefield at the same time as Rampaging Ferocidon, its last ability triggers.

Rulings via Scryfall

• WO
  Wizards of the Coast2018-05-10

  Rampaging Ferocidon 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. Part of what made these cards so powerful in Standard was the ability to play multiple copies and build highly efficient, consistent decks around them. Source: https://magic.wizards.com/en/news/news/future-brawl-2018-05-10
• WO
  Wizards of the Coast2018-01-15

  Rampaging Ferocidon was banned in standard on January 15, 2018. In analyzing the evolution of the metagame over time as well as contrasting pre- and post-sideboard game win percentages, we have determined this to be one of the cards that most discourages and invalidates counterplay against the deck. While Rampaging Ferocidon may have been an appropriate answer card in a more powerful metagame that contained that combo, it has instead proven to cause collateral damage against other decks aiming to counter aggressive red strategies. Source: https://magic.wizards.com/en/news/news/january-15-2018-banned-and-restricted-announcement-2018-01-15
• WO
  Wizards of the Coast2019-08-26

  Rampaging Ferocidon was unbanned in standard on August 26, 2019. We periodically review the banned and restricted lists for cards we can remove that will positively impact a format. Rampaging Ferocidon was banned during Ixalan-year Standard in order to weaken aggressive red decks and provide more counterplay by blocking with creatures and gaining life. Since that time, aggressive red decks have become weaker in the metagame as stronger and more varied strategies have emerged. Source: https://magic.wizards.com/en/news/news/august-26-2019-banned-and-restricted-announcement-2019-08-26