Drake-Flock Migration

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

At the beginning of your end step, you may exile up
to X instant and/or sorcery cards from your
graveyard with a migration counter on them, where
X is equal to the power of target Army creature
token you control. You may cast spells with
migration counters on them from exile.