Istfell's Well of Lost Futures

Spells players cast from their hand cost {2} more
to cast.
Each nonland card in each player's hand has
foretell. Its foretell cost is equal to its mana cost reduced by {2} for each other foretold card their
controller owns in exile.
{2}: Look at up to one face down card you don't
own. Any player may activate this ability.