Your opponent decides what to discard, both during the resolution and indirectly by deciding which cards to hold back on their turn as fodder for further discard spells
With trample, the difference between the trampling creature's strength and the blocking creature's toughness is dealt to the opponent
This ability is a great fit for one of the most popular, and perhaps most unique MTG commanders in Edge of Eternities, however: Ragost, Deft Gastronaut
At the end of the exchange, you will have a Tarmogoyf and a mystery card
She provides a definite clock by creating emblems that deal continual damage to your opponent, she can wipe the board, and she can serve as an answer to larger creatures or even planeswalkers
Let's take a look at what we can do with it besides just watch it tick down as our opponents try and pummel us into oblivion