This change in dynamic can often give the Hammer player a substantial advantage.* *This is a concept known as a "subgame," or a game within a game (gameception), and is a subject that has been written about a bit in the past by myself and others and may be worth revisiting
Mewtwo takes 20 additional damage from Darkness-type attacks
Cheap Countermagic Flusterstorm, Swan Song, and An Offer You Can't Refuse are premier examples of cheap countermagic that let you interact on a tight budget, mana-wise
is for merfolk decks, since dragons dont typically get a bunch of good, cheap plays
Getting a Field of the Dead or Nykthos, Shrine to Nyx out of your deck could warp the game to your advantage drastically
It doesn't have to be the same player, planeswalker, or battle that The Grim Captain is attacking