The Rage of Battle

Hideaway 6 (When this enchantment enters the battlefield, look at the top six cards of your library, exile one face down, then put the rest on
the bottom in a random order.)
Whenever you attack with an army with
power 7 or more you may play the exiled
card without paying it's mana cost
At the beginning of each end step, Amass 1, unless an opponent lost life this turn.