Cast Harmless Offering by paying ({2} magic symbol) ({R} magic symbol) , giving control of Moderation to an opponent.
Whenever the opponent that controls Moderation casts a spell from their hand, Knowledge Pool triggers, exiling that spell.
Because Moderation prevents the opponent from casting more than one spell each turn, the opponent cannot cast the spell permitted by Knowledge Pool, or any other spell that turn.
Results
Exile all spells cast from target opponent's hand.