Magic Word

As Magic Word enters the battlefield, secretly choose a word. (That's not an article or preposition.)
At the beginning of each end step, if a player said the word, put a verse counter on Magic Word. Otherwise, remove a verse counter from it.
Pay 3 life: Guess the word. If correct, the next spell each player casts this turn has cascade and costs {1} less per verse counter. Exile Magic Word. Activate only if you don't control Magic Word.