Thought Harvester
{3}{U}
Creature — Eldrazi Drone
Oracle Text
Devoid (This card has no color.)
Flying
Whenever you cast a colorless spell, target opponent exiles the top card of their library.
Watch Out
Cast trigger fires even if counteredWatch Out
This triggers when the spell is cast, before it resolves. Even if the spell is countered, the cast trigger still resolves. Copies of spells are not cast, so they won't trigger this.