your opponent takes no damage until the end of the next turn after this card resolves, also, you look at your opponent's hand and all monsters they control, and if you do, destroy the monsters among them
NOTE: Selection is random
The letter grade typically ranges from A to D
However, there will be other effects depending on what the attached cards abilities are
With some careful deck building (mostly playing some big card-draw spells you can cycle into with Unpredictable Cyclone to make sure you always have some cycling cards in hand), you should be able to mostly play your entire deck in a single turn by cycling, casting stuff (including card-draw spells) for free with Unpredictable Cyclone, drawing into more cycling cards, and cycling them to trigger Unpredictable Cyclone against and again until you've essentially cast your entire deck
If you're looking to stay at the casual level with this deck or pump it up to something more competitive with a Thassa's OracleThassa's Oracle combo, this is a good place to start