Norin and Feldon is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

, : Create a token that's a copy of target creature card in your graveyard, except it's an artifact in addition to its other types, gains haste, and has "Whenever a player casts a spell or a creature attacks, exile this token." Activate only as a sorcery.