Atraxa, Praetor's Champion

Eminence - Whenever you Proliferate, if Atraxa, Praetor's Champion is in the
command zone or on the battlefield, you way Proliferate an additional time. (This Proliferate trigger cannot target itself.)
Flying, Vigilance, Deathtouch, Lifelink,
Infect.
{g/w}{w/u}{u/b}{b/g}: Proliferate, then tap target permanent.