Liar's Pendulum

• WWizards of the Coast2004-12-01
  Official Ruling
  After the opponent has guessed, you may reveal your hand. If your opponent was wrong, you draw a card. If your opponent was right, you don’t draw a card.
• WWizards of the Coast2004-12-01
  Official Ruling
  You can’t draw a card if you don’t reveal your hand.
• WWizards of the Coast2004-12-01
  Official Ruling
  You reveal your hand only if you choose to, regardless of whether your opponent guessed right or wrong.
• WWizards of the Coast2004-12-01
  Official Ruling
  First you name a card. Then the targeted opponent guesses whether the card is in your hand.

Rulings via Scryfall