Petrion Harbinger of Vengeance

Vigilance
During the end step, if Petrion, Harbinger of Vengeance did not attack or block this turn, transform it.
{1}{b} Petrion, Harbinger of Vengeance gains double strike until the end of the turn.
"He got really quiet all of a sudden, and his eyes seemed to empty. Suddenly, the giant didn't seem like the biggest problem."
-Raz'el, Harbinger of Peace