The Phyrexian Negator is one of Phyrexia's most notorious creations. Negators were created for the sole purpose of tracking and destroying planeswalkers. Early negators were crude in design, but, like all of Phyrexia's minions, they improved as the ages passed. Negators were the chief operatives during the Phyrexian attack on the original Tolarian Academy, and were later chiefly used in Phyrexia's attempts to destroy Urza before the Phyrexian Invasion. During the Invasion itself, however, they were used very scarcely, if at all.