Thrawn, Chiss Tactician

When Thrawn, Chiss Tactician enters the battlefield and at the beginning of your upkeep, each opponent exiles a card at random from their hand. They may cast those cards
for as long as they remain exiled.
Spells you cast that target one or more spells
cast from exile cost {w}{u} less to cast.
Spells your opponents cast from their hands
cost {1} more to cast.