Goblin Warren-Rousing

At the beginning of your upkeep, amass Goblins 1.
(Put a +1/+1 counter on an Army you control. It is
also a Goblin. If you don't control an Army, create
a 0/0 black Goblin Army creature token first.)

At the beginning of your end step, discard up to X
cards, where X is equal to the power of target Army
creature token you control, then draw cards equal to
the number of cards discarded this way.