GRN Guild Kit

Circu, Dimir Lobotomist

Whenever you cast a blue spell, exile the top card of target player's library.
Whenever you cast a black spell, exile the top card of target player's library.
Your opponents can't cast spells with the same name as a card exiled with Circu, Dimir Lobotomist.

Whenever you cast a blue spell, exile the top card of target player's library.
Whenever you cast a black spell, exile the top card of target player's library.
Your opponents can't cast spells with the same name as a card exiled with Circu.

Ravnica: City of Guilds

Whenever you play a blue spell, remove the top card of target library from the game.
Whenever you play a black spell, remove the top card of target library from the game.
Your opponents can't play nonland cards with the same name as a card removed from the game with Circu, Dimir Lobotomist.