If you cast a spell "without paying its mana cost," you can't pay any alternative costs
This makes it incredibly useful with cards that rely on charge counters for value, like Lux Cannon, Magistrate's Scepter, or Astral Cornucopia
I think back to how stupid Yargle and Multani looked at first, yet it ended up doing nothing in March of the Machine
Released in the very first set of the game, Dark Ritual is a staple in every format it's legal in, from the casual Commander format to the highest-powered formats of Legacy and Vintage
Theyre pretty straightforward in design
Not every Blue deck is going to be about casting Instants and Sorceries, but the ones that are will want this to hand