How do I know
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
To make the best out of our strategies, we can further amplify them by adding cards that support many of our strategies and that is easy since those strategies collide
The reward for your mana investment is 1/1 copies of whatever you kill
Mix Atraxa, Grand Unifier, a multi-format all-star, with one of the most iconic video game villains of all time, and you have potential for a serious price tag
Your opponent trades their Colossal Dreadmaw with Ojer Taq to kill each other in combat, its death trigger will bring the god back as Temple of Civilization, and the additional trigger from Teysa Karlov will do nothing because Ojer Taq is no longer in the graveyard