Skolanos, Keragon's Mentor

If the first card you draw each turn is an aura you
may reveal it as you draw it, if you do, you may
cast it without paying its mana cost.
Whenever you cast an aura spell, if no mana was
spent to cast it, creatures you control gain double
strike and vigilance until end of turn.
{g/w}{g/w}{g/w} {t} : Sacrifice an aura, enchanted
permanents you control gain indestructible until
end of turn.