Petra, Heir to Winter's Heart

Flying
Eminence: At the beginning of the game your life
total becomes 20 and whenever you cast a snow
spell you gain a shield counter, your life total can
never become more than 20. All damage you deal
is increased by the number of shield
counters you have.
{3}{s}{w}{u}: Exile target God creature and then transform Petra, the backside of Petra still
contains the Eminence ability of the frontside.