If a player plays a party card, you can respond by removing creatures in their party on the board
This includes targeting their permanents, graveyards, spells, and libraries
So if you are looking here for competitive deck inspiration, know that the Thunder Dragon deck is no longer a great option due to its best cards being banned for competitive play
You could ask: Are you going to attack me this turn? Do you have a counterspell in your hand? Are you able to win the game this turn? If I were to ask you if you concede the game, would your answer to that question be the same as the answer to this question? Spark Fiend is hilarious because its not entirely clear what the card does, why it does it, or how it does it
I hope this allowed you all to see me in a slightly different light
Collecting them all just took a dangerous twist